Learning aspect in Italian as additional language. The role of second languages

The study examines the role played by English and Romance languages (L2s) when learning grammatical aspect in Italian as additional language (Ln). Swedish university students of Italian (n = 34), divided according to knowledge of a Romance L2 and English aspectual knowledge, completed an interpretation task of aspectual contrast in Italian. Eight native speakers served as a control group. The findings showed that knowledge of a Romance language as L2 and high English aspectual knowledge exerted a differential influence on learning aspect in Italian. This outcome is discussed in the light of a consistent form-meaning relationship between the L2s and Italian. Yet, with a mismatch between grammatical and lexical aspect, the learners’ judgments differed from the native speakers’ judgments. Thus, our findings also support the idea of the existence of differential learning paths sustained by the L2s when learning complex aspectual configurations.


Introduction
In the present study, we seek to contribute to the understanding of the role played by formerly learnt second languages (L2s) when learning grammatical aspect in Romance focusing on Italian as additional language 1 (Ln). The L2s investigated here are English and Romance languages. Two specific aims are formulated; firstly, to investigate whether the acquisition of grammatical aspect in Italian as Ln is influenced by knowledge of another Romance language as L2 and secondly, whether it is influenced by aspectual knowledge in English.
In previous research, the acquisition of grammatical aspect has mostly been approached from a more classical second language acquisition (SLA) perspective, emphasizing how cross-linguistic (dis)similarities between the first language (L1) and the target language (TL) can, at least to some extent, explain individual differences in learning outcomes. However, the question as to whether the knowledge of previously learnt L2s may influence the acquisition of grammatical aspect in an Ln has not yet received sufficient attention. Although a few studies have shown that there was transfer of knowledge from the L2s to the Ln in the realm of aspect (Diaubalick et al. 2020;Eibensteiner 2019;Foote 2009;Salaberry 2005;Vallerossa 2021), these studies focused either on the role exerted by aspectual knowledge level in L2 English (Eibensteiner 2019), or by additional knowledge of a Romance language (Diaubalick et al. 2020;Foote 2009;Salaberry 2005;Vallerossa 2021). The influence of both English and Romance languages in learning aspect in another Romance language is yet to be addressed. Moreover, there is no agreement on whether transfer of knowledge from the L2 to the Ln is an across-the-board phenomenon or if it is restricted to specific aspectual contexts, so called prototypical associations.
Therefore, the present study investigates what role aspectual knowledge in English L2 and knowledge of a Romance L2 exert on the Ln acquisition of grammatical aspect in Italian. The acquisition of grammatical aspect was investigated among university students 2 of Italian Ln in Sweden. As a matter of fact, in the 1 Additional language (Ln) here refers to any language that is learnt after the L1, and at least one L2, regardless of the order of acquisition. The abbreviation L3 (or L4) refers instead to the chronologically third (or fourth) language approached by a learner. The labels additional language learning/acquisition are used interchangeably to refer to the process of appropriation, among speakers with knowledge of at least one L2, of a new non-native language. 2 Not all students in the present study had Swedish as L1. Other L1s were Russian, French, Romanian and Persian. The students who had other L1s than Swedish were nonetheless highly proficient in Swedish (from advanced to nativelike according to a sociolinguistic questionnaire). A passing grade in Swedish or Swedish as a second language from upper secondary school is the admission requirement for undergraduate studies in Italian in Sweden.
Swedish university context, Italian is approached as an additional foreign language; for example, proficiency in English comparable to the B2.1 level in the Common European Framework for Languages (Council of Europe 2001) is a requirement for eligibility. Besides, it is not uncommon for students of Italian to have prior knowledge of another Romance language (Bardel 2006;Vallerossa 2021). Hence, all the L2s known by undergraduate Swedish students may potentially be activated and influence the subsequent acquisition of Italian. In this study, we focus on the role played by English L2 and Romance L2s. The learners who participated in the present study were divided into two groups depending on whether they had knowledge of another Romance L2 besides Italian or not. One group consisted of learners of Italian L3 with knowledge of English as L2 (henceforth, the non-Romance group). The other group consisted of learners of Italian L4, with knowledge of English and another Romance language (either French or Spanish) as L2s (henceforth, the Romance group). 3 There was also a control group of Italian native speakers as a point of reference in the analysis of the data. Data to measure aspectual knowledge in Italian were gathered through an interpretation test. Aspectual knowledge in English was controlled through an interpretation test in English.
The theoretical background for the study is twofold. On the one hand, it takes as a point of departure the 'Lexical Aspect Hypothesis' (Andersen 1993), its subsequent refinements (Bergström 1995;Domínguez et al. 2013;Kihlstedt 1998), and more recent contributions emphasizing the role of the L1 (McManus 2011(McManus , 2015. On the other hand, these studies are integrated in current research on Ln learning. We focus on three relevant factors in Ln acquisition, namely how L1 acquisition is inherently different from L2/Ln learning in terms of processes of language appropriation (Bardel and Falk 2007), the role exerted by linguistic typology (Rothman 2011) and the role of L2 proficiency in Ln learning, here understood in a narrow sense as knowledge of aspectual contrasts in English.

Codification of grammatical aspect in Romance languages, Swedish and English
Tense refers to the external temporal structure expressed by a verb (Smith 1997) whereas grammatical aspect indicates "the different ways of viewing the internal temporal constituency of a situation" (Comrie 1976: 3). The present study concerns the acquisition of past tense-aspect morphology, whereby we only focus on aspectual distinctions in the past domain, although aspectual differences can also be found in the present ('I read/I am reading') and in the future ('I will read/I will be reading'). Aspectual information is codified differently across languages. It is expressed morphologically in Romance languages, as they distinguish, in the past tense, between perfective and imperfective tenses (e.g., passato prossimo/imperfetto in Italian, passé composé/imparfait in French, pretérito indefinido/imperfecto in Spanish). 4 Romance perfective tenses convey perfective aspect, by presenting a situation as a whole, together with its endpoints as in example (1) below. Imperfective tenses in Romance languages express imperfective aspect, by presenting a situation from the inside, without its endpoints (Comrie 1976). The focus of the present study is on two types of imperfective aspect: progressive aspect, which expresses ongoingness as in (2), and habitual aspect, which expresses habituality as in (3). 5 Due to this correspondence between tense and aspect in the past domain, a speaker of a Romance language "will automatically take an aspectual perspective" (Giacalone Ramat 2002: 225), by presenting the situation as either perfective (1) or imperfective (2, 3). Moreover, there are progressive periphrases in Romance languages expressing progressive aspect, such as the Italian stare + gerund and the Spanish estar + gerund (Bardovi-Harlig and Comajoan-Colomé 2020: 3).
4 The Romance languages investigated here realize perfective aspect differently when it comes to surface forms. The perfective past tense is analytic in French and Italian but synthetic in continental Spanish (Bertinetto 1986;Squartini and Bertinetto 2000). However, following previous research on second and additional language acquisition of aspect, we consider Romance languages as a unitary group (see for example Ayoun and Salaberry 2005). In fact, Romance languages mark the aspectual contrast perfective/imperfective in the past obligatorily and morphologically, which makes them intrinsically different from Germanic languages, such as Swedish, that do so lexically (see for example Diaubalick et al. 2020). 5 Some scholars (Bertinetto 1986;Squartini 1998) make a distinction between progressive and continuous aspect. Progressive aspect presents an ongoing situation in a single point in time and continuous aspect presents an ongoing situation along a wider time span. Following the argumentation of McManus (2011: 124, footnote 19), based in turn on Comrie (1976), we consider continuous aspect a type of lexical aspect, rather than a grammatical aspect, as it occurs exclusively with stative predicates.
(1) As child, Mike played (Imperfective) football. 'As a child, Mike used to play football. ' Foote (2009: 91) In Swedish, there is no such correspondence between tense and aspect. Swedish has one ambiguous past tense, the preteritum, expressing perfective aspect (4) and imperfective aspect, in both its progressive and habitual meanings. When it comes to imperfective aspect, Swedish also has, besides the preteritum, different lexical devices. The progressive meaning can be expressed through the periphrastic construction with hålla på att + infinitive (5) ('to keep' + Ving) and through postural verb constructions with the verbs sitta, stå, ligga ('sit, stand, lie') (6) (Blensenius 2009(Blensenius , 2013Ebert 2000). The habitual meaning can be expressed by the modal bruka in the past (brukade, i.e., 'used to') followed by an infinitive as in (7) (Altenberg 2007 English is situated somewhere in between Romance languages and Swedish when it comes to aspectual distinctions. Contrary to Romance languages but similar to Swedish, there is no explicit aspectual morphology in English. Nonetheless, English has a basic aspectual distinction in the past between the Simple Past and the Past Progressive (Comrie 1976). The Simple Past in English can convey both perfective aspect (8) and the habitual meaning of the imperfective aspect (9). Alternatively, habitual aspect can be conveyed by the construction 'to use to + infinitive' and by the modal 'would' + infinitive (9). Unlike Swedish, English obligatorily marks the progressive meaning of the imperfective aspect in the past by means of the Past Progressive ('to be' + Ving) (10).
(9) As a child, Mike played (used to/would play) football.
(10) I was dancing tango while Gianni was singing.

The L2 acquisition of aspect in Romance languages
Over the past two decades, much research on the acquisition of tense-aspect morphology has been conducted in the light of the Lexical Aspect Hypothesis (henceforth, LAH; Andersen 1993). Following the LAH, lexical aspect, i.e., the intrinsic aspectual value of a verb predicate (Comrie 1976), orients the acquisition pattern of grammatical aspect. According to the model, when learners begin to express tempo-aspectual relationships through verbal morphology, they start producing perfective morphology, generally along with telic predicates, as 'to open' (Comrie 1976: 45). Perfective morphology is eventually extended to atelic predicates, as for example the verb 'to play'. Within atelic predicates, perfective morphology is first attached to activities, i.e., dynamic atelic verbs as 'to run', and subsequently to stative predicates, i.e., non-dynamic atelic verbs as 'to be'.
Imperfective morphology appears at a later stage and follows an opposite pattern, appearing primarily with stative predicates and activities and at a final stage with telic predicates (Andersen 1993;Shirai and Andersen 1995). The pattern as described by the LAH has been criticized and refined through the years. For example, it has been pointed out that the LAH is rather representative of the interlanguage of advanced learners, and not of beginners (see Salaberry 2000). Instead, learners initially rely on a default past tense form regardless of lexical aspect (see Wiberg 1996 for the unmarked past tense hypothesis, and Salaberry 2000 for the Default Past Tense Hypothesis). Another point made by some scholars (Bergström 1995;Domínguez et al. 2013;Kihlstedt 1998) is that learners select tempo-aspectual morphology based on the contrast dynamic/non-dynamic, rather than on the dichotomy telic/atelic. This was the case of learners of Romance languages (French and Spanish) with English (Bergström 1995;Domínguez et al. 2013) and Swedish (Kihlstedt 1998) as L1s. In both production and interpretation tasks, learners consistently selected perfective morphology with eventive predicates [+dynamic], a category including both telic verbs and activities, and imperfective morphology with stative predicates [-dynamic].
More recent contributions have highlighted the role played by the typological proximity between the L1 and a target Romance language. By comparing learners of the same TL but with different L1s (e.g., McManus 2011, 2015 for L1 German and L1 English learners of French; González and Quintana Hernández 2018 for L1 Dutch and L1 English learners of Spanish), these studies have provided evidence that an L1, which is typologically similar to the TL, has a bootstrapping effect on the acquisition process. Indeed, positive transfer from the L1 in the realm of aspect was evident both across-the-board among Hispanophone learners of French (e.g., Izquierdo and Collins 2008) and on particular aspectual configurations, where learners could beneficially rely on specific form-meaning relationships between the L1 and the TL (e.g., McManus 2015). One such case is the progressive meaning of the imperfective tense in French (imparfait). This meaning was learnt relatively late by Swedish university students in Kihlstedt's study (1998). In contrast with her results, Howard (2005) found that English L1 speakers learning French acquire this meaning at an earlier stage. These different outcomes have been interpreted considering that English, but not Swedish, encodes progressive aspect morphologically which facilitates, for an English L1 speaker, the remapping process of the progressive meaning onto a Romance language (Labeau 2005).
What these studies provide evidence for is that both the semantic properties of verb predicates (i.e., telicity/dynamicity) and cross-linguistic differences between the L1 and the TL have an influence on the acquisition of grammatical aspect in Romance languages. With the exception of a few studies (Diaubalick et al. 2020;Eibensteiner 2019;Foote 2009;Salaberry 2005;Vallerossa 2021), however, the majority of studies on the acquisition of aspect have been conducted from a more classical SLA perspective, thus disregarding the role played by formerly learnt L2s. The present study aims to fill an important research gap by shedding light on the role exerted by the L2s, namely English and Romance languages, when learning grammatical aspect in Italian as Ln. The next section focuses on transfer in subsequent language learning by looking at three factors: L2 proficiency, language typology, and the L2 status factor. 4 Additional language learning and transfer in the Ln acquisition of aspect

Models of additional language learning
Unlike true L2 acquisition where transfer 6 can only derive from the L1 (Odlin 1989: 27), in Ln learning transfer phenomena can originate in both the L1(s) and the L2(s) (e.g., Cenoz 2001;Ringbom 2001;Williams and Hammarberg 2009). Another difference between true L2 acquisition and Ln acquisition is that they entail qualitatively different processes of language appropriation, as a multilingual speaker, in contrast to a true L2 learner, already has experience of one or several non-native languages (Bardel and Falk 2012;Bardel and Sánchez 2017;Hammarberg 2001;Hammarberg 2018;Hufeisen 2018;Jessner 2003). The multilingual speakers' experience as language learners provides them with a set of specific competencies. For instance, they have generally a high degree of metalinguistic knowledge, i.e., conscious knowledge about formally learnt languages (Paradis 2009: 39), and crosslinguistic awareness, meaning that they are generally more capable of detecting similarities and differences between any formerly known languages and the Ln than bilingual speakers (Jessner 2006: 116). These competencies can all be strategically exploited in approaching a new language, where knowledge of multiple languages is involved (Jessner 2003). Models of Ln learning emphasize different factors as responsible for the activation of certain linguistic sources in a multilingual speaker. This section focuses on the role of proficiency, typological proximity and the L2 status factor in Ln learning. However, in the present study, the two latter factors are not investigated separately. Instead, we focus on the interplay between typological proximity and the L2 status. We conclude the section by briefly presenting two recent models of Ln learning, namely the Scalpel Model (Slabakova 2017) and the Linguistic Proximity Model (Westergaard 2021), both models assuming that transfer is not a holistic phenomenon but it occurs property-by-property.
The proficiency factor for transfer entails both previously learnt L2s and the TL. As for the L2s, a high level of proficiency in the L2 is generally assumed to facilitate its transferability into a new language (Bardel and Lindqvist 2007;Sánchez 2020). However, there is also evidence that transfer may come from a low-proficiency L2, especially when the L2 and the TL are typologically similar to each other (see for example Lindqvist and Bardel 2014 for transfer from a weak L2). As for TL proficiency, transfer generally decreases as learners become more proficient in their TL. In fact, learners are likely to consistently rely on previously known languages when they are yet to fully develop their TL knowledge (Williams and Hammarberg 2009).
According to the Typological Primacy Model (Rothman 2011), linguistic proximity is the strongest predictor in Ln learning. In for example Rothman's study from 2011, there were two groups of L3 learners of Portuguese and Spanish, with L1 English/L2 Spanish and L1 Italian/L2 English, respectively. The results provide evidence for transfer from a typologically similar language, i.e., Italian L1 for the L3 Spanish group and L2 Spanish for the L3 Portuguese group.
The L2 status factor hypothesis (henceforth, L2SFH, Bardel and Falk 2012) posits a strong role of the L2s in Ln syntactic transfer. At the core of the L2SFH is the declarative and procedural model (Paradis 2009), according to which there is an inherent difference between L1 acquisition and second/subsequent language learning. L1 acquisition involves unconscious mechanisms of language appropriation, leading to implicit linguistic competence, namely the ability to use language without knowledge of the actual underlying mechanisms (Paradis 2009: 38). It is supported by the procedural memory system. Second/additional language learning later in life is determined by explicit processes of language appropriation and involves metalinguistic knowledge, i.e., knowledge of explicit facts about language. It is sustained by the declarative memory system. According to the L2SFH, it is more likely for the L2s to be activated in Ln learning than for the L1, since the L2s and the Ln have the same processes of language appropriation (Bardel and Falk 2012). In their study (2007), Bardel and Falk found evidence for the L2 status factor by examining the placement of the negation by L3 learners of Swedish and Dutch, both verb-second (V2) languages. By comparing two mirrorimage learner groups with the V2 structure in the L1 and in the L2, they argue for the L2 status factor, as the group with a V2 language as L2 transferred this structure in their L3 to a significantly higher extent than the group with a V2 language as L1.
Finally, there are two recent transfer models that are important to mention, namely the Scalpel Model (henceforth, SM, Slabakova 2017) and the Linguistic Proximity Model (henceforth, LPM, Westergaard 2021). In a nutshell, both models argue against the idea of wholesale transfer, which is maintained by the TPM. As mentioned above, the TPM argues that the entire grammar of a previous language is transferred during the initial stages of Ln learning due to perceived linguistic similarity. Conversely, both the SM and the LPM assume that Ln learning is an incremental property-by-property phenomenon. Specifically, they contend that neither the L1 nor the L2 has a privileged role in Ln learning. Instead, transfer is hybrid, that is, it may come from either the L1 or the L2 depending on the structure taken in consideration. Several factors are deemed as responsible for the selection of a source language. For example, structural similarity between certain properties is considered as fundamental in the LPM, while the SM also points out the importance of other external factors, e.g., input frequency or instruction. Further, both models concur on that transfer may be positive or negative, the latter due to misleading comparisons between a previously acquired language and the TL.

Transfer in the Ln acquisition of aspect
The L2SFH and the Typological Primacy Model have been adopted in two studies (Eibensteiner 2019;Foote 2009), both dealing with the Ln acquisition of the contrast perfective/imperfective in Romance languages. There are three additional studies (Diaubalick et al. 2020;Salaberry 2005;Vallerossa 2021) adding another relevant layer to the Ln acquisition of aspect, i.e., the role of prototypical associations. The studies by Diaubalick et al. (2020), Foote (2009), Salaberry (2005 and Vallerossa (2021) take knowledge of a Romance L2 into account, whereas the study by Eibensteiner (2019) focuses on the role played by aspectual knowledge in English as L2. Diaubalick et al. (2020) tested a group of native speakers (n = 149) and three groups of German L1 speakers with no knowledge (n = 15), basic (n = 39) and advanced (n = 19) knowledge of a Romance language as L2. Data was a written 40-item discourse-based forced-choice task with prototypical and nonprototypical combinations. The results showed that the higher the knowledge of the Romance language, the closer the learners' selection of TA morphology was to the control group for prototypical associations. However, for non-prototypical associations, all learner groups behaved differently from the native speaker group, which is connected to a persisting detrimental effect from the L1, namely German. These results are interpreted in the light of different systems underlying the acquisition of prototypical and non-prototypical aspectual configurations (for a similar argument, see Salaberry 2020). While the acquisition of prototypical meanings is sustained by explicit knowledge and can be influenced by transfer from the L2s in line with the L2SFH, non-prototypical meanings are negatively constrained by the L1 German, which lacks inflectional morphology.
Foote (2009) compared three groups of learners of Romance languages with different language constellations and a control group of native speakers on a morphology test and a sentence conjunction judgment task. In the sentence conjunction task, imperfective Romance tenses (i.e., imperfetto in Italian, imparfait in French, imperfecto in Spanish) made the sentences logical, while perfective Romance tenses (i.e., passato prossimo in Italian, passé composé in French, pretérito indefinido in Spanish) made them illogical. As for lexical aspect, Foote included stative verbs and telic verbs, the latter further divided into accomplishments and achievements. Of the three learner groups, one had English as L1 and was tested in a Romance language they had studied as L2. The remaining groups were two mirrorimaged learner groups of a Romance L3; one group had English as L1 and a Romance language as L2 whereas the other group had a Romance language as L1 and English as L2. The L3 groups completed both tasks in two Romance languages, whereas the L2 group was tested in one Romance language. In line with the Typological Primacy Model (Rothman 2011), the L3 groups performed in a similar way to the native group and were significantly more accurate than the L2 group, whether the Romance language was their native or non-native language. Compared to the L3 groups and the native speaker group, the L2 group was less straightforward in judging illogical sentences (i.e., those sentences including perfective tenses) with telic verbs. They were also insecure when judging both illogical and logical sentences, the latter containing imperfective tenses, with stative verbs. In brief, transfer of knowledge was attested across typologically similar languages. Salaberry (2005) tested the influence of L2 Spanish on L3 Portuguese among English L1 speakers through a verb-selection task of a comic strip. A distinction was made in the study between English eventive verbs, which can receive perfective and imperfective morphology (Simple Past/Past Progressive), and stative verbs, which instead seldom occur in forms other than the Simple Past. An overall positive influence of L2 Spanish on L3 Portuguese was found among these participants but difficulties were found with associations of Preterit and stative verbs, i.e., non-prototypical associations. As for non-prototypical contexts with stative predicates, L1 transfer overrode transfer from the L2s, as these learners detrimentally relied on the L1 English and established erroneous connections of one form/one meaning as in their L1.
The study by Vallerossa (2021) focused on the interplay between linguistic typology, TL proficiency and prototypes in learning aspectual contrasts in Italian as Ln. Twenty-five undergraduate students were divided into four groups depending on a combination of knowledge of a Romance language as L2 (Romance; non-Romance) and proficiency level in Italian (low-proficiency; high-proficiency). The results from an oral retelling story test showed that both prototypes and knowledge of a Romance L2 interact with TL proficiency. Specifically, knowledge of a Romance L2 had a boosting effect on the emergence of the imperfective tense among low-proficiency learners while, among high-proficiency learners, such knowledge helped learners moving past prototypes with the perfective tense.
Finally, Eibensteiner (2019) investigated the influence of L2 English on L3 Spanish by L1 German speakers, adopting two sentence interpretation tasks of aspectual contrasts, one in Spanish and one in English. The latter allowed for a distinction between low and high English achievers. Significant differences between these groups were found in contexts presenting one form/one meaning relationships between English and Spanish. The German learners of L3 Spanish performed well in both prototypical and non-prototypical contexts, which is explained in the light of a positive L2 influence.
Foote (2009) emphasizes the positive influence of having knowledge of a language that is typologically similar to the TL, whether it is an L1 or an L2. Although this positive influence was evident in her study across all combinations of grammatical and lexical aspect, stative predicates were those generating greater difficulties among students without previous knowledge of a Romance language.
The study by Vallerossa (2021) (2021), the L2 is more similar to the target L3 in its ways of codifying aspect than the L1. Hence, it is not possible to disentangle whether the L2, namely English in Eibensteiner (2019) and a Romance language in Vallerossa (2021), has a privileged role due to its relative closeness to the TL as regards aspect, its status as a L2, or a combination of both factors.
The studies by Salaberry (2005) and Diaubalick et al. (2020) are useful to understand the differential role exerted by the L1 and the L2, in relation to aspectual combinations. In their studies, knowing a Romance language as L2 resulted in positive transfer, but only with prototypical associations. Instead, an L1 codifying aspect in a way different from the TL manifested its detrimental effect in the case of non-prototypical associations. Following their argumentation, there are two developmental patterns; one pattern regarding prototypical associations, where knowledge of additional languages may usefully be exploited, and one pattern involving non-prototypical associations, which are persistently constrained by the L1 (cf. Salaberry 2020: 60).
In summary, the aforementioned studies indicate some type of influence from previously known languages and contribute to the understanding of different dimensions involved in the learning of aspect in an Ln. However, there is no agreement on whether transfer is holistic or limited to certain types of associations (i.e., property-by-property), and on the factors that are responsible for transfer (i.e., the status of a language as L1/L2 or typological proximity).

The study
The issues discussed above form the background to the present study, which investigates the role exerted by the L2s, namely English and Romance languages, on the Ln acquisition of grammatical aspect in Italian.
As mentioned, the study juxtaposes results from learners of Italian with results from native speakers. Because aspect is highly context-dependent, the native speakers' representation of aspect is not dichotomous and their judgments do not always tend to be black-and-white (Foote 2009: 91, 110). Hence, it was deemed very important to include a control group when analyzing the results from the tests, in order to reveal native speakers' preferences in relation to aspectual judgments.

Research questions
We address the following two research questions: RQ1: Are there differences between learners of Italian as Ln, with and without knowledge of another Romance language as L2 and Italian native speakers regarding the interpretation of the semantic meanings entailed by tempo-aspectual morphology in relation to lexical aspect? RQ2: Are there differences between learners of Italian as Ln, with low aspectual knowledge in English as L2 and high aspectual knowledge in English as L2, regarding the interpretation of the semantic meanings entailed by tempo-aspectual morphology in relation to lexical aspect? 6 Methods

Participants
The participants in this study (N = 42) were undergraduate learners of Italian Ln with previous knowledge of L2 English (n = 34) and a control group of Italian native speakers (n = 8). There were 23 female and 11 male participants. Their age ranged from 20 to 76 (M = 42.6; SD = 18.74). Five participants who responded to an advertisement on social media were studying or had studied Italian privately or through educational associations (Studieförbund). The remaining twenty-nine participants were recruited from seven undergraduate courses of Italian. Although there is no official comparability between each undergraduate course and proficiency level according to the Common European Framework for Languages (Council of Europe 2001), the most advanced undergraduate course (i.e., the Bachelor thesis course in Italian) roughly corresponds to the advanced level C1 (see also Vallerossa 2021). The distribution of these participants was as follows: nine participants were recruited from the first preparatory course of Italian, three from the second preparatory course, six from Italian I, four from Italian II, four from Italian III, two from Italian IV and one from the Bachelor thesis course in Italian (Kandidat). Given the variation in study background and current study level of Italian, a C-test in Italian (see Section 6.2) served as a general measure of the participants' level of proficiency. All the Ln learners of Italian had advanced knowledge of Swedish, and knowledge of a Romance L2 for the Romance group. Twenty-six participants had Swedish as L1, four participants had two L1s, one of which was Swedish, and four participants had another L1 but were highly proficient in Swedish. 7 The learner group was divided into two subgroups: a non-Romance group (n = 12), consisting of learners of Italian L3 with previous knowledge of English as L2, and a Romance group (n = 22), including learners of Italian L4 with knowledge of English and another Romance language as L2s (either French or Spanish). The labels L3/L4, however, only refer to the languages controlled for in the present study and are not to be considered as absolute indicators of all the languages known by the participants. In fact, many participants reported previous knowledge of other languages 8 in a 7 As for the participants with two L1s, one L1 was Swedish and the other was a Romance language. The L1s of the participants without Swedish as L1 were Russian, French, Romanian and Persian. We are aware that including learners with a Romance language as L1 or one of the L1s complicates the analysis in this study. The exclusion of some participants would make the sample cleaner, but in this study, which aims to investigate the role exerted by the L2s, we found it valuable to strive for ecological validity. The sample represents the real composition of multilingual students' background languages in the current context. 8 In the sociolinguistic questionnaire, the participants were asked to report previously learnt languages and to self-assess their proficiency level in these languages as for comprehension (reading, listening) and production (writing, speaking) on a five-point Likert scale with the values "I am not at all able to"; "beginner"; "intermediate"; "advanced" and "nativelike". A mean between the four skills was calculated in order to determine their proficiency level in these languages. Twelve participants reported knowledge of German, of which nine on a level between "I am not at all able to" and "intermediate", and three on an advanced level. Two participants had sociolinguistic questionnaire (Ancient Greek, Arabic, Chinese, Bosnian, Croatian, Serbian, Dutch, German, and Russian). The participants chose which group they wanted to belong to after having received oral and written information about the selection criteria for each of the two learner profiles (Romance/non-Romance). Although the non-Romance group participants decided to be classified as such, several participants in this group reported some basic knowledge of another Romance L2 from studies in school. 9 This general multilingual background is not surprising as Italian in Sweden, as has already been mentioned, is almost never approached as the chronologically third language, but it is generally preceded by studies in several other foreign languages (Bardel 2006).

Tests
To measure the learners' knowledge of Italian aspect, an Italian interpretation test (IIT), inspired by the SPLLOC project (Domínguez et al. 2013), was conducted. The participants were presented with an aspectual situation, here referred to as 'task'. Each task consisted of two parts: an aspectual context written in English 10 and an Italian target sentence. Aspect, as expressed in the context, could be perfective, knowledge of Ancient Greek, one reporting a level corresponding to "I am not at all able to", and the other attesting a beginner level. One participant reported a beginner level of proficiency in Dutch. One participant reported that she was not able to communicate orally in Chinese, while she was able to read it and write it on a beginner level. The same held true for another participant's skills in Arabic. Six participants reported knowledge of Slavic languages (Russian, Bosnian, Croatian and Serbian). As pointed out by two anonymous reviewers, knowledge of Slavic languages may be problematic. However, the proficiency of the majority of these participants in a Slavic language was very limited. Hence, transfer from these languages is unlikely. 9 We are aware that allowing the participants to decide to what group they wanted to belong may be problematic, not least considering that students in the non-Romance group reported some basic knowledge of another Romance language. It is important to point out that the participants were provided with oral and written information about the selection criteria for each group. We assume the knowledge of a Romance language reported by students in the non-Romance group to be very limited. Hence, we consider the participants' self-report as a valid indication of their knowledge of a Romance language. 10 To use English in the context, and not Italian or Swedish, was decided after several considerations. Not having the context in the TL was based on Domínguez, Arche and Myles (2017), Eibensteiner (2019) and McManus (2011). There are essentially two reasons behind such a decision. First, it was done to avoid priming effects by having the same language in the context and in the target sentence, as discussed in Domínguez et al. (2017: 454 in footnote 15) and Eibensteiner (2019: 12 in footnote 1). Second, this decision is justified in order to ensure that learners would understand the context, as even beginners were included. The native speaker group did not have knowledge of Swedish. Therefore, English was chosen.
Learning aspect in Italian as additional language imperfective progressive or imperfective habitual. In relation to every context, the participants were presented with an Italian target sentence summarizing the context, but substituting the verb with a blank. The missing verb was presented to the participants in three different tenses, here referred to as 'items'. The participants had to judge how appropriately, on a four point Likert-scale (completely/rather (in) appropriate), the three different verb tenses would describe the context. The option "I do not know" was provided with the indication of not overusing it, as it would determine the exclusion from the analysis (see Figure 1 below).
As for lexical aspect, the verb predicate was telic or atelic. The atelic predicates were either stative predicates or activities when inserted in a perfective or habitual aspectual context. 11 In a nutshell, every task, consisting of a context and a target sentence, had three items, every item specifying a particular configuration of tense (passato prossimo, imperfetto, periphrasis), grammatical aspect (perfective, imperfective progressive, imperfective habitual) and lexical aspect (telic, activity, stative).
In total, the test consisted of 16 tasks, each one of these consisting of three items. The test also included four filler tasks that were removed from the analysis. Further, four items expressing another past tense form (i.e., the passato remoto) were also removed from the analysis. That left 32 items for the analysis. Two versions of the test were created and subsequently balanced so that some learners received one version of the IIT and others received the other version. Figure 1: Example of an aspectual situation from the Italian interpretation test. The English sentence expresses a habitual aspectual context, and the participant is asked to use an atelic activity verb (mangiare 'to eat') and judge the acceptability of the verb in three different tenses: passato prossimo, imperfetto and the periphrastic construction.
11 For the imperfective progressive context, the atelic verbs were all activities as the progressive periphrasis in Italian is ungrammatical with stative predicates.
In Table 1, we report the 21 combinations of aspect, tense and lexical aspect tested. Some combinations were expected to yield high acceptance rates while other low. Those combinations where high acceptance rates were expected were: passato prossimo in perfective contexts, imperfetto in habitual and progressive contexts, and the periphrastic construction in progressive contexts. Instead, passato prossimo in habitual and progressive contexts, imperfetto in perfective contexts, and the periphrastic construction in perfective and habitual contexts were expected to yield negative responses. Generally, in this type of data, the native speakers' interpretations are considered as a reference point against which to compare the learners' interpretations.
Aspectual knowledge in English was measured by an English interpretation test (EIT) similar to the one in Italian, which was inspired by Eibensteiner (2019). The EIT tested knowledge of the English aspectual contrast between perfective and progressive aspect, as expressed by the contrast Simple Past/Past Progressive. There were 15 tasks in the EIT. Each task consisted of a context in Swedish and two target sentences, one with the Simple Past and one with the Progressive Past. Only one condition rendered each sentence acceptable. The sentences tested five perfective one-time contexts (three telic; two atelic) with the Simple Past providing Learning aspect in Italian as additional language a correct interpretation and seven progressive contexts (three telic, four atelic) with the Progressive Past providing a correct interpretation. Further, there were three distractor tasks.
In order to ensure that the learner groups did not differ as for proficiency level in Italian, they completed a test inspired by the C-test (henceforth referred to as C-test [Klein-Braley 1985) in Italian. The C-test, inspired by Bardel et al. (work in progress) and Ågren et al. (2021), consisted of two short texts containing 31 blanks each for a total of 62 blanks. All the tests were performed online through the platform 'itslearning' for the C-test and Google forms for the interpretation tests.

Group divisions
For the analysis, the learner group (N = 34) was divided into learners with low aspectual knowledge (LAK) in English (n = 15) and learners with high aspectual knowledge (HAK) in English (n = 14). The sample was divided into these two levels based on the median of the EIT (Mdn = 18). 12 As mentioned above (see Section 6.2), the learner groups completed a C-test as a measure of proficiency in Italian. As shown in Table 2, no significant difference was found between these groups regarding proficiency in Italian. Hence, the groups had comparable knowledge of Italian. 12 Five learners scored at the median in the EIT. The intent here was to make a clear distinction between two learner groups by testing English aspectual knowledge. Therefore, these five learners were excluded from the analysis since placing them in either the LAK or HAK group would imply an arbitrary decision.

Procedure
The study was cross-sectional. The non-Romance group and the Romance group completed the C-test in Italian, the EIT and the IIT. While data from the non-Romance group were collected during one session, data from the Romance group were gathered in two sessions. 13 The native speaker group only completed the IIT. First, one of the researchers contacted Italian instructors at a Swedish university and briefly presented the project to undergraduate students from different levels. The participants who showed interest were subsequently contacted by the researcher with detailed written information and then gave their informed written consent. Finally, the same researcher met each participant online, either alone or in small groups. During the meeting, the participants performed the tests in the presence of the researcher. There was no time limit for the tests. Time of completion was approximately 1 h per participant.

Results
Interpretation rating means for all combinations and all participants in the IIT were calculated and used as the dependent variable in both research questions. Research question 1 investigated whether there were differences between learners of Italian as Ln, with and without knowledge of another Romance language as L2 and Italian native speakers regarding the interpretation of the semantic meanings entailed by tempo-aspectual morphology in relation to lexical aspect. The independent variables were group (non-Romance, Romance, native) and the different combinations. Research question 2 examined whether there were differences between learners of Italian as Ln, with low aspectual knowledge in English as L2 and high aspectual knowledge in English as L2, regarding the interpretation of the semantic meanings entailed by tempo-aspectual morphology in relation to lexical aspect. The independent variables were aspectual knowledge of English (low versus high) and the different combinations.
Missing values were substituted by imputation, using the mice package in R. Missing data constituted 1% of the total number of values, and in total, 9 missing values were substituted. All statistical analyses were run in R (version 1.1.423). Table 3 shows the mean ratings for the different combinations computed for the native, Romance and non-Romance groups. It must be noted that some combination values are expected to be low, and judged as inappropriate, while others are expected to be high and judged as appropriate.
In general, it can be noted that the native speakers' judgments were more straightforward than the leaners' judgments, except for the combination habitual.passatoprossimo.activity. While learners tended to accept correct combinations in a vein similar to the judgments of the native speakers, e.g., perfective aspect with passato prossimo or progressive aspect with the periphrasis, they were not as decisive as the native control group when it came to reject incorrect combinations, e.g., progressive aspect with passato prossimo. Difficult aspectual judgments for the learner groups encompassed combinations of perfective aspect with imperfetto, habitual aspect with passato prossimo and telic predicates, and habitual aspect with the periphrasis and activity predicates.
A two-way mixed ANOVA was conducted using the afex package, with combination as a within-participant variable and group (natives, Romance, non-Romance) as the between-participant variable. Mauchly's test indicated that the assumption of sphericity had been violated; therefore, degrees of freedom were corrected using Greenhouse-Geisser estimates of sphericity. Analyses showed a main effect for combination, F (5.85, 228.16) = 46.07; p < 0.001, partial η 2 = 0.520. The analysis also resulted in an interaction effect between group and combination, F (11.70, 228.16) = 1.88; p = 0.040, partial η 2 = 0.081. No significant main effect was found for group, F (2, 39) = 2.16; p = 0.129, partial η 2 = 0.009.
As regards the interaction effect, pairwise comparisons, conducted with the emmeans package, revealed four statistically significant differences in three combinations. There was a significant difference between the native speaker group and the non-Romance group (p < 0.05) for the combination habitual.passatoprossimo.activity. The native speaker group tended to accept this combination (M = 2.88; SD = 0.83) to a significantly higher degree than the non-Romance group (M = 1.92; SD = 1). A significant difference was found between the non-Romance group and the native speaker group (p < 0.05) for the combination habitual.passatoprossimo.telic. The non-Romance group accepted this combination (M = 2.46; SD = 1.21) to a significantly larger extent than the native speaker group (M = 1.38; SD = 0.52). Finally, there was a significant difference between the native speaker group and the non-Romance group (p < 0.05), and the native speaker group and the Romance group (p < 0.01), for the combination perfective.imperfetto.stative. The native speaker group tended to reject this combination (M = 1.63; SD = 0.74) to a significantly higher degree than the non-Romance group (M = 2.75; SD = 0.97), and the Romance group (M = 2.77; SD = 1.19). No other statistically significant differences were found. Table 4 shows the mean ratings for the different combinations computed for the LAK group (low aspectual knowledge in English) and the HAK group (high aspectual knowledge in English).
Generally, both groups were more likely to accept correct combinations than to reject incorrect combinations, e.g., the combination with perfective and passato prossimo obtains rather high acceptance rates. Further, it can be noted that the HAK group overall was more decisive in their judgments than the LAK group. The HAK group tended to both accept correct combinations and refuse incorrect combinations more consistently than the LAK group. The most difficult aspectual judgment concerned the combination perfective.imperfetto.stative, where both groups seemed to be rather indecisive. The judgments yielding greatest group discrepancies entailed habitual aspect combined with passato prossimo and progressive aspect combined with both imperfetto and passato prossimo.
As regards the interaction effect, pairwise comparisons, conducted with the emmeans package, showed statistically significant differences for six combinations; two combinations included habitual aspect and four combinations included progressive aspect. A significant difference was found for the combination habitual.imperfetto.activity (p < 0.05), which was accepted by the HAK group (M = 3.86; SD = 0.53) to a significantly higher extent than by the LAK group (M = 3.20; SD = 1.26). Further, there was a significant difference for the combination habitual.passatoprossimo.telic (p < 0.001), with the HAK group rejecting it to a higher extent (M = 1.32; SD = 0.58) than the LAK group (M = 2.50; SD = 1.22).

Discussion
The present study investigated what role knowledge of a Romance L2 and aspectual knowledge in English exert on the Ln acquisition of grammatical aspect in Italian. In the discussion, we present the significant differences connected to these two factors separately.

Knowledge of a Romance language as L2
Our first research question addressed differences between learners of Italian as Ln, with and without knowledge of another Romance language as L2 and Italian native speakers regarding the interpretation of the semantic meanings entailed Learning aspect in Italian as additional language by tempo-aspectual morphology in relation to lexical aspect. This was tested with the IIT. The results showed significant differences for three combinations. Two of these differences were with habitual aspect, namely the combinations habitual.passatoprossimo.activity and habitual.passatoprossimo.telic. These combinations were expected to yield negative responses.
Starting with the combination habitual.passatoprossimo.activity, it was accepted by the native speaker group to a significantly higher extent than the non-Romance group. A similar outcome revealing uncertainty by native speakers has been attested in previous research (Foote 2009: 110). This result helps understanding the complexity of judging aspectual contrasts, which is not straightforward for native speakers either. 14 The case of the combinations habitual.passatoprossimo.telic is different because it was incorrectly accepted by the non-Romance group to a higher extent than the Romance group and the native speaker group. With this combination, there is congruence at the level of the predicate between lexical and grammatical aspect, and a clash with the overarching habitual perspective. Although learners in the non-Romance and the Romance group had comparable knowledge of Italian (cf. Section 6.3), additional knowledge of a Romance language seems, in our case, to offer an advantage in the realm of aspect. The non-Romance group's judgments tended to be based on congruence at the level of the predicate, i.e., telic verbs drawing perfective morphology. The Romance group, similarly to the native speakers, tended instead to rely more consistently on the aspectual contrast at a sentential level. If compared to the postulates of the LAH (Andersen 1993), the Romance group seems more mature, aspectually speaking, than the non-Romance group; their judgments are less reliant on the predicate and instead tend to account 14 It is important bearing in mind that there is an intrinsic ambiguity in how the notion of repetition/iteration may be represented; it can be conceptualized either in terms of repeated, piecemeal occurrences or as a holistic unit. In the former case, the aspectual notion is that of iterativity, and it is conveyed in Romance languages by perfective morphology, whereas in the latter, it is habituality, which is expressed by imperfective morphology . This distinction however, is subtle and both interpretations are virtually acceptable. The indecisiveness attested in the responses by the native speakers with habitual.passatoprossimo.activity arguably reflects this ambiguity. Consider, for instance, the habitual context in the sentence 'Pablo loved playing football when he was young. He played at least three times a week for many years'. Both statements 'Pablo ha giocato a calcio' ('he played football' Perfective) and 'Pablo giocava a calcio' ('he played football' Imperfective) are true in Italian with reference to the context, the difference being the focal point. In the former case, the focus is on the actual occurrence of the eventuality, i. e., the fact that, according to the context, it is true saying that Pablo played football, whereas in the latter the emphasis is on the general habit depicted as unitary, i.e., playing football intended almost as a characteristic of Pablo.
for the complex aspectual constellation of the sentence (see also Rosi 2008 for a similar outcome regarding intermediate and advanced learners of L2 Italian). Also, the advantage of the Romance group is manifested with habitual aspect, which may be indicative of positive transfer from other Romance languages, which codify habitual aspect morphologically as Italian.
Finally, a significant difference was found for the combination perfective.imperfetto.stative between the native speakers and both learner groups. Hence, no L2-related differences connected to Romance languages were found and both learner groups behaved similarly. Crucially, neither knowledge of a Romance language as L2 nor English aspectual knowledge seems to influence the learning of these associations (see Table 4). This suggests that learning these associations might be influenced by factors other than L2 knowledge. Arguably, it could be due to a negative influence exerted by Swedish, which is the L1 of the majority of the learners. If so, our results would align with those of Salaberry (2005 and Diaubalick et al. (2020). We believe that the differential path of acquisition proposed by Salaberry (2005 and Diaubalick et al. (2020) might operate for multilingual Swedish-speaking learners of Italian as well. In this case, both Swedish and the L2 English would contribute to negative transfer. In fact, like German, Swedish also lacks inflectional morphology, which complicates the acquisition of non-prototypical contexts (Diaubalick et al. 2020). Moreover, high aspectual knowledge of English does not play any role when it comes to nonprototypical meanings, since dynamic and stative predicates are differentially marked in English. While dynamic predicates occur in both Simple Past and Past Progressive, stative predicates are usually inflected in the Simple Past, which, according to Salaberry (2005), would make learners more conservative in employing stative verbs with one tense form. Further, the consistent preference of imperfective morphology with stative predicates reflects semantic principles (Congruence Principle: Andersen 1993) and was also found in studies on Italian as a TL (cf. Banfi and Bernini 2003;Giacalone Ramat 1990). This study, however, differs from Salaberry (2005) and Diaubalick et al. (2020) in such a way that it does not seek to distinguish between L1 and L2 influence.
What we found evidence for is that knowledge of a Romance language L2 does not seem to play a role for these associations, suggesting that both learner groups detrimentally rely on the aspectual representations characteristic of other previously known languages lacking aspectual contrasts. Nonetheless, we did not control for level of aspectual knowledge in the learners' Romance language. Learners might not have grasped this particular aspectual contrast in their Romance L2 in the first place. Arguably, their knowledge of a Romance L2 may not suffice for transfer into an Ln in the case of this particular combination.

Aspectual knowledge of English
Our second research question concerned whether differences could be found between learners of Italian as Ln, with low aspectual knowledge in English as L2 and high aspectual knowledge in English as L2, regarding the interpretation of the semantic meanings entailed by tempo-aspectual morphology in relation to lexical aspect. This was investigated through differences in results from the IIT that could be traced back to aspectual knowledge in English as L2. Six significant differences were found, two in relation to habitual aspect and four in relation to progressive aspect. In all the cases, high aspectual knowledge in English translated into responses more similar to those provided by the native speakers.
As for habitual aspect, HAK students were more prone to correctly reject the combinations habitual.passatoprossimo.telic and accept the combination habitual.imperfetto.activity to a significantly higher extent than the LAK group. Although English does not encode habitual aspect morphologically, it has a device marking habitual aspect (i.e., 'to use to'), which arguably bootstrapped the correct remapping, for the HAK group, of habitual aspect onto the target imperfetto, and not onto the passato prossimo (see Eibensteiner 2019: 80 for a similar argument regarding the English periphrasis). However, it could be the case that the existence of the construction with bruka in Swedish could be deemed as responsible for this outcome as well. In this case, there would be positive transfer from both Swedish and English.
Further, four significant differences were found with progressive aspect; here, HAK learners outperformed LAK learners in both accepting the imperfetto and rejecting the passato prossimo. As mentioned in Section 6.2, having in-depth knowledge of the English aspectual system corresponded, in the present study, to having knowledge of perfective and progressive aspect in English, as expressed by the contrast Simple Past/Past Progressive. Our data indicate that having aspectual knowledge in English results in being able to grasp the notion of progressive aspect and attaching it correctly onto a target form, in our case the Italian imperfetto. This finding can be connected to studies focusing on crosslinguistic (dis)similarities between the L1 and the TL. More specifically, it echoes the results from Labeau (2005), who argues that the existence of a periphrastic construction in the learners' L1 (i.e., English, as in Howard 2005) facilitates the acquisition of the progressive meaning entailed by the imparfait whereas its absence would complicate it as it does for learners with Swedish as L1 (Kihlstedt 1998). Our data corroborate this hypothesis, but we have found that such an effect does not only derive from having an L1 that realizes progressive aspect morphologically, but may also originate in an L2, as long as learners have grasped this contrast in their L2.

Conclusions
Overall, our results are in line with transfer studies in the realm of aspect, attesting a positive influence derived from L2s that are typologically proximate to the TL, when the structures in question are similar. In our case, this was reflected in a positive influence from knowledge of a Romance L2 (Foote 2009;Salaberry 2005;Vallerossa 2021) and from having high aspectual knowledge in English as L2 (Eibensteiner 2019(Eibensteiner , 2021. Our results do not allow contrasting transfer models based on the status of different languages, i.e., the L1 and the L2s, since a few students did not have Swedish as L1. Nonetheless, we found L2-related differences between groups, i.e., between the Romance group and the non-Romance group, for prototypical associations. Instead, when dealing with non-prototypical associations, there are no L2-related differences, which suggests that other factors, seemingly the L1, might be responsible for how these associations are interpreted. As mentioned above, this result would be in line with Salaberry's hypothesis (2005Salaberry's hypothesis ( , 2020 about the existence of differential learning patterns for prototypical and non-prototypical associations; learning prototypical associations may be sustained by knowledge in formerly learnt languages whereas learning non-prototypical associations is constrained by the L1. Ultimately, Salaberry (2020) ties his model of differential learning paths to distinctive mechanisms of language appropriation, as sustained by the L2SFH: "[…] the non-linear type of learning associated with complex aspectual concepts is representative of the type of implicit language knowledge not readily available through focused metalinguistic awareness activities (either in the L2 or the L3). In contrast, the linear process of learning documented […] for the prototypical meanings of aspect shows the effects of metalinguistic information available in the L2 and the L3" (p. 55) Likewise, in our study, we find support for the L2SFHcombined with typological proximity between the L2 and Italianand the role exerted by L2 proficiency (Hammarberg 2001) in the sense of aspectual knowledge in English as L2. In line with the L2SFH, the data support the idea of transfer derived from non-native languages, in our case English and Romance languages. Knowledge from formerly learnt L2s translated into positive transfer, but it did so in differential ways (cf. Eibensteiner 2021). While both factors led to a correct remapping of habitual aspect, English aspectual knowledge also contributed to positive transfer of progressive aspect. These results suggest that the existence of consistent formmeaning relationships in the L2s (imperfective tenses in Romance languages; the device 'to use to' and the periphrasis in English) fosters positive transfer onto new forms in the TL. The fact that both knowledge of a Romance L2 and high aspectual knowledge in English led to positive transfer in the case of habitual aspect does not allow us to single out whether the main source language of influence was English or a Romance language. Learners with high aspectual knowledge in English and with knowledge of a Romance L2 are likely to be equipped with a high degree of crosslinguistic awareness (Jessner 2006), enhancing their capability of detecting similarities and differences between previously known languages and the TL (cf. Bardel 2005;Izquierdo and Collins 2008: 364).
Crucially, the same results, e.g., the existence of differential learning paths for different linguistic structures, also align with models contending that transfer occurs property-by-property, and not holistically, namely the SM (Slabakova 2017) and the LPM (Westergaard 2021). However, both models also maintain that the L1 and the L2 may contribute to transfer, which cannot be tested in the present study, given the multifaceted linguistic background of our multilingual learners. In particular, our data corroborate the tenets of the SM, according to which certain structures, in our case the prototypical associations, are easier to be acquired while other structures, that are the non-prototypical associations, are more difficult to be appropriated. While the LPM maintains that abstract (structural) similarity is a discriminating factor for determining the potential transfer source, the SM also accounts for other external factors, such as abundance of a structure in the input, that is, positive evidence, and negative evidence. According to this hypothesis, prototypical associations are easier to acquire than non-prototypical ones due to their saliency and input frequency. Although both models have been criticized for lacking predictive power (see for example Bardel and Falk 2020), our data provide clear evidence for property-by-property transfer, hence suggesting that these models represent viable departure points for future transfer studies. In particular, the present study represents a first step for getting closer to a deeper understanding of hybrid transfer, which, in the aspectual domain, has to be related to all previously known languages and to the notion of prototypicality (cf. Vallerossa and Bardel in preparation). In order to do so, future research will ideally have a more refined design including larger groups with different language constellations. For example, one consistent group of students with a Romance language as L1, Swedish/English as L2s, and Italian as Ln, could be compared with another group of students with Swedish as L1, English/a Romance language as L2s, and Italian as Ln. Another limitation of the present study is connected to the fact that some learners reported knowledge in languages, other than English and a Romance L2, that codify grammatical aspect. Controlling for this variable would allow testing the hypothesis that predicts differential transfer effects determined by different language sources. Finally, in future studies, it would be important to investigate how the effects determined by aspectual knowledge in the L2s vary depending on the students' proficiency in Italian. Due to the limited pool of students available in the current project, it was not possible to control for the effects of L2 aspectual knowledge among groups with varying proficiency levels (see Vallerossa 2021, submitted for publication).
Some implications for language education arise from the results of the study. Relying on knowledge from the L2s turned out to be an advantage in judging aspectual contrasts in Italian. These findings shall be framed within the Swedish university context, where Italian is usually approached as an additional foreign language, after studies of English and not seldom of another Romance language. The results suggest that the teaching of Italian (and other modern languages) may be supported not only by comparisons with Swedish but also with other L2s. What is proposed here is a strategic deployment of the L2s in order to raise crosslinguistic awareness. This purpose can be served by referring to constructions, which are familiar to students (e.g., 'be' + Ving), and by explicitly teaching how the codification of aspect varies across languages.