The third wave of studies on DOM in Romance

contact with Quechua, in Misiones, where Portuguese and Guaraní are contact languages. The data from the contact varieties are compared with data from predominantly monolingual speakers from Lima and Montevideo. Their results suggest that the different contact scenarios had different effects on the DOM system of the speakers from those regions. While Quechua L1 speakers from Cusco show a rather rudimentary DOM system in general, Misiones differs from predominantly monolingual varieties in terms of greater inter-speaker variability. The study highlights the importance of collecting controlled and comparable data for DOM in comparative studies and shows that different constructions need to be treated differently

research on DOM moves from a semasiological, language-specific view to an onomasiological perspective and to general principles of grammaticalization. Thus it was recognized that DOM grammaticalizes similarly in very different languages, with the two factors of animacy and definiteness being the most determinative. And DOM as a general marking strategy does not depend on a prepositional marker, but may be expressed through different devices.
What, then, is the third wave like? In Romance linguistics, there are two main directions for recent studies on DOM. On the one hand, researchers go back to apparently established issues and take a closer, more fine-grained look at the data. Typological generalizations have opened up new perspectives, but in doing so they have also broadened the horizon towards related phenomena. The interplay of different means of object differentiation within the same language is studied (e.g. clitic doubling or "indexing" vs. traditional "flagging" DOM, i.e. marking by an element that immediately stands by the object). Not only objects are considered; instead, whole constructions are also taken into account. And newly identified factors such as agentivity, telicity and affectedness are considered when looking closely at language variation. On the other hand, new methodological perspectives have been opened. In historical studies, the availability of large corpora makes it possible to work with comprehensive databases and to identify statistically relevant factors, while in studies concerning contemporary usage, experimental methods allow for controlled studies with fine-grained manipulations.1 In the next Section, we will introduce current issues that characterize the third wave of DOM studies in Romance: the debate about the general concept (2.1), the conditioning factors (2.2), more fine-grained and comparative approaches to variation (2.3) and to contact (2.4), and methodological innovations (2.5). Section 3 then relates the contributions of this volume to the issues introduced in Section 2.

Current issues in the studies of Romance DOM 2.1 What is DOM and what is it not?
In his contribution to this volume, Bossong points out that a crucial moment in his attempt to understand the Spanish "prepositional accusative" (1) was to look at it from a rather abstract perspective: differentiation of elements within one syntactic function or argument.
(1) a. Veo *Ø/a la guitarrista. see.prs.1sg dom the.fem guitar player b. Veo Ø/*a la guitarra. see.prs.1sg dom the.fem guitar This differentiation is conditioned by a number of factors, but rather than getting lost in the complexity of the interaction of the different factors, Bossong highlights the availability of a differentiation device. From this general perspective, the device marks prominent (or non-prototypical) objects. Such devices exist in a series of Romance languages whose grammatical characteristics overlap to different degrees. This group consists of varieties of Portuguese, Spanish, Catalan, Sardinian, Italian, Rhaeto-Romance and Romanian. With the exception of Rhaeto-Romance, all these languages are discussed in the present volume and exemplification can be found in the respective chapters.
Bossong's abstract conception at the same time serves quite well as a comparative concept for typology (Haspelmath 2010), and soon many other languages with such devices were "discovered", by Bossong and other researchers. It also was pointed out that such differentiation also exists for subjects in some languages (Differential Subject Marking) and both notions were brought together under the term Differential Argument Marking (DAM, cf. Witzlack-Makarevich/ Seržant 2018 for an overview). In typology, the notion is usually understood in a broader sense than in Bossong's work, where the device is characterized by traditional conditioning factors (above all, animacy and definiteness), a morphological marker (so-called "grammemic marking") and certain grammaticalization paths. The success of the broader application of the term in typology, and the discussion of more and more grammatical configurations as instances of this very same sort of device, made it necessary at some point to introduce entire DAM typologies (Witzlack-Makarevich/Seržant 2018). Eventually, the broader approach made its way back into Romance linguistics. Bossong himself had already identified clitic doubling as a second DOM system in Spanish. More recently, other phenomena from the object domain have been added and discussed in terms of DOM, includ-ing Spanish leísmo (Flores/Melis 2007, among others), null vs. overt objects in Portuguese (Schwenter 2014), and most recently, Differential Goal Marking in Spanish (Melis/Rodríguez Cortés 2017). All these phenomena feature splits in the object domain and can be related to the semantic hierarchies from the seminal work of Silverstein (1976). As it turns out, most of these phenomena, when occurring in other Romance DOM languages, could also be related to the notion of DOM in one way or another.
However, these phenomena are also different in many ways and it is not always clear what insights are gained for the description/analysis of language-specific grammars when subsuming all such phenomena under one (umbrella) term. If we accept the idea that all the aforementioned phenomena instantiate DOM, only a small number of Bossong's constituent features for the definition of DOM remain valid. The idea of a common grammaticalization pathway must be excluded and therefore also the idea that DOM systems may arise when the case system of a language collapses, as occurred in Latin, since this idea applies to flagging DOM in Romance, but not necessarily to other types. The condition of the split being realized by a privative opposition with a grammatical morphemic marker is obviously also obsolete under the umbrella view. The common remaining core for a definition or the insight, therefore, is the manifestation of some sort of split in the object domain localized on the Silverstein hierarchies.
Since many (if not all) of these phenomena exist in different Ibero-Romance languages, and also differ from language to language, the same question applies at the level of the language family. For instance, if all the phenomena are instances of DOM, the question arises as to whether this multiple and extraordinarily subtle differentiation is a special feature of (Ibero-)Romance or whether other DOM languages, once subjected to a comparable fine-grained analysis, will also show multiple differentiations, maybe of different kinds, in the object domain. As a further abstraction or generalization, it has been observed that the marking of non-prototypicality is not restricted to the arguments of a verb. DOM or DAM, on this view, could be seen as a consequence of the universal tendency in grammar to mark prominent elements with longer forms (Haspelmath 2020). However, the more abstract this unifying typological account becomes, the more phenomena it leaves unaccounted for in comparison to Bossong's more restricted definition and explanation. Thus, DOM seems not only to be conditioned by multiple factors, but it is also a concept applied at different levels of linguistic description. The typologist's DOM is not always identical to what is understood as DOM in Romance linguistics, and the same holds for the application of the concept to individual Romance grammars.

"Local" and "global" factors
Depending on how widely the notion of DOM is understood, the factors to be taken into account when studying it will be different. However, what will remain relevant is an overall distinction between "local" and "global" factors (Laca 2006, 430). "Local" factors refer to the characteristics of the marked or unmarked object NP, whereas "global" factors include a larger context within the sentence or even beyond. As far as this distinction is concerned, the history of DOM studies is not linear, and there seems to be a certain back and forth in terms of focus, or a coexistence of studies centring on different aspects. If we look at studies of the first wave, the principal interest lies in the characteristics of the objects. However, there is also a long tradition which claims that the main purpose of DOM is distinguishing subjects and objects in languages which lack other morphological devices for this purpose; thus, analyzing it will involve the whole sentence. A pioneering view in this sense can be seen in Lenz (1920), where it is claimed that the semantic characteristics of the object NP derive from the higher principle of differentiation. The fact that animate objects are more frequently marked than inanimate ones would then not be primarily due to the need to mark animates, but rather to the higher frequency of animate objects in constructions with animate subjects. Frequency-based accounts of typologically dominant construction patterns seem to confirm this view (Jäger 2004;Hogeweg/ de Hoop 2010apud García García 2014. Of course, this will affect the emergence rather than the later distribution of DOM. Recent studies, most notably by García García (2014) (cf. also Kabatek 2016) pick up these traditional ideas and reinterpret them in new theoretical frameworks. Whereas local factors were considered primarily due to their easier cross-linguistic comparability during the second wave, the third wave returns to more contextual views, including factors that surpass the sentence level and look at the informational status of the object referent within a larger context. The contributions in this book consider both local and global factors, including combinations of both.

Languages and varieties
While the tendency of the first wave was to look at languages such as Spanish, Portuguese or Romanian as a whole, and to consider variation basically from a diachronic point of view, the second wave broadened its scope to embrace a global perspective and found DOM languages throughout the world. At the same time, within the Romance area, DOM was identified in several diatopic varieties. The third wave looks not only at the coexistence of DOM devices within the same language or dialect, but also at variation phenomena within one historical language. The most salient example is probably Spanish, where DOM is described in synchronic grammars as a generalized phenomenon without much local differentiation. There is a tradition that in a very general way claims DOM to be more frequent or to function differently in American Spanish in comparison to Peninsular Spanish (Kany 1951;Company Company 2002;von Heusinger/ Kaiser 2005); however, general judgments about "two Spanishes" remain very vague, and variational patterns of DOM appear to be more complex than generally assumed. Of course, a distinction is necessary between the core functions of DOM and the possible zones of variation. Once we enter more marginal zones, it becomes more difficult to access enough comparable data. This is why new methodological approaches have recently addressed marginal phenomena comparing diatopic variation with an objectively comparative experimental setting (cf. Section 2.5.).
If we look at the other dimensions of variation, we must recognize that less is known about DOM and diastratic variation. Generally speaking, DOM in Romance is generally not a "marker" or a "stereotype" in a Labovian sense (Labov 1972), and only rarely do we find metalinguistic comments on DOM outside of linguistics, in more general discussions of language use. On the diaphasic level, DOM (and particularly flagging DOM) might acquire the value of a stylistic marker, especially in those contexts where it is clearly optional and where it seems to add an expressive surplus (Pottier 1968;Kabatek 2016). This seems to be the case, for instance, in the preference of marking salient toponyms (such as a España). However, such idiosyncratic cases should be separated from the functional view on the system of a language or variety.

Contact
A still rather poorly explored aspect of DOM is whether it is sensitive to language contact, and if so which of the dimensions elucidated above are receptive to such influence. In the context of this volume, it seems reasonable to make a distinction between DOM as a factor of convergence (or divergence) within the closely related Romance languages on one hand, and contact across language families on the other.
Comparison between Romance languages being the essence of what we have called the first wave of DOM studies, the question of contact and the internal typology of Romance languages naturally comes into play. Although the scattered distribution of DOM within Romance -particularly the rather isolated instance of Romanian -does not necessarily suggest a specific geographic point of origin, some of the earlier accounts did suggest that Romance DOM might lead back to a pre-Latin substratum, either Iberic (Criado de Val 1954) or of an supposed Mediterranean origin (Meier 1948;Niculescu 1959). However, this explanation is obviously problematic due to its notoriously speculative nature. Instead, the attention of Romance scholars shifts to contact between Romance languages, where the Iberian Peninsula with the dominant presence of Spanish and its highly grammaticalized DOM alongside "smaller" languages represents a most promising area of research. In a comprehensive diachronic corpus study on DOM in Portuguese, Delille (1970) aligns the intensity of Spanish-Portuguese language contact and the evolution of object marking in Portuguese. Initially lagging behind its twin language as DOM expands in medieval Castilian, Portuguese DOM shows a sudden rise of marked objects during the Iberian Union (16 th to 17 th century), only to return largely to the initial prevalence after Portuguese independence was restored, thus suggesting that DOM is easily amenable to contact-induced language change. Although this hypothesis raises many questions in the light of new accounts on DOM, it remains largely unchallenged (cf. Aldon/Della Costanza 2013;Döhla 2014;Pires 2017). East of the Castilian domain, the case of Catalan is a more controversial one, since it is less proximate to Spanish from a typological perspective, but prone to longer and more intense contact. Hence, Catalan DOM has long been considered as a "barbarism", not only by (mainly Catalan) grammarians, but also by linguists. However, recent studies have shed light on its own, autochthonous structural evolution. In this volume, the papers by Anna Pineda and Senta Zeugin give a differentiated account of the matter, the former from a diachronic, the latter from a synchronic point of view.
With the second phase of DOM studies, contact across language families came to the fore. In this field, results are even more inconclusive. Several studies suggest that DOM is difficult to acquire in L2 settings and that interference between languages with and without DOM occurs even in early childhood bilinguals, such as heritage speakers in the US or Quechua natives fluent in Spanish (Montrul/Bowles 2009;Ticio 2015; Wall/Obrist, this volume). On the other hand, the presence of an original DOM system in L1 appears to facilitate the acquisition of another in L2, even if the respective splits present structural divergences (Montrul/Gürel 2015). Whether or not social bilingualism can facilitate the development of DOM in a contact language is a largely unexplored issue (cf. Döhla 2011), and completing the picture will require further empirical fieldwork, such as the contribution of Mayer/Sánchez to this volume and the experimental study reported by Wall/Obrist.

Methodological innovations
At approximately the same time that the term DOM was coined, an overview article on the prepositional accusative in Spanish (Pensado 1985, 18) noted that no sociolinguistic study on this topic had yet appeared. The author suspected that the reason for this might be that researchers were unsure whether it was indeed possible to find any clear sociolectal distributions or even to simply document the generalization of the marker with this methodology. Things have changed considerably since then. Not only do we have a series of sociolinguistic studies from different regions for Spanish (Tippets 2011;Balasch 2011, among others), diachronic research has also documented the contribution of several of the factors in the generalization of Spanish DOM (Laca 2006;Della Costanza 2015) and, to a lesser degree, for Catalan (Pineda, this volume) and Portuguese (Delille 1970;Pires 2017). Furthermore, Ibero-Romance DOM has more recently begun to be studied with experimental approaches, including off-line methods such as controlled acceptability judgment tasks, picture verification tasks, elicitation tasks (Montrul 2013;Hoff 2018;Zeugin 2018; Bautista-Maldonado/Montrul 2019, among others), but also on-line processing studies, for instance making use of EEG (Nieuwland et al. 2013). However, many of these studies of the third wave are pioneering work and the new methods are still in an exploratory phase.
One issue in all corpus-related research -either diachronic or sociolinguistic -is the highly skewed distribution of DOM markers. As a marker of nonprototypical objects, its general frequency is not expected to be very high. More problematic, though, is that most examples that occur represent a limited set of configurations, and for many of the relevant factors contemporary corpora are not able to provide sufficient occurrences. This is not likely to change as long as DOM cannot be annotated automatically in very large corpora. Even in the largest "manual" diachronic studies, only the impact of the major factors can be traced across the centuries (Laca 2006;Della Costanza 2015). A somewhat different approach is to restrict the search in diachronic corpora to a specific factor and to analyze a fixed number of occurrences of relevant examples per century. Von Heusinger/Kaiser (2011) have shown that it is possible to trace the impact of more subtle factors this way, but of course it is then difficult to relate these results to other factors. As long as different approaches are explored as a means of identifying different and more subtle factors, the collected datasets will inevitably remain heterogeneous. In the longer term, a standardization of the approaches will be necessary in order to bring the different isolated findings into perspective.
The variational and sociolinguistic literature has shown that it is indeed possible to obtain robust results. Many of the factors discussed in the theoretical literature have been found to be empirically relevant, and different impacts for these factors have been discovered in different samples of speakers. For instance, marking seems to be more frequent in certain places of the Americas, such as Mexico and the River Plate, than in Spain (Tippets 2011, among others), and less frequent in others, such as Cuba and perhaps the Caribbean more generally (Alfaraz 2011; Caro Reina/García García/von Heusinger, this volume). However, the corpus problems mentioned above also persist in this field to a certain degree. First, there are no standards for corpus selection, corpus cleaning or annotation. This will be necessary in the future in order to obtain comparable datasets. Second, infrequent DOM-sensitive constructions are very difficult to document. Finally, even if larger quantities of occurrences of rather rare configurations are made available at some point, another problem arises, namely that of the statistical treatment of variables when one of them is very dominant in absolute numbers. Balasch (2011), for instance, discusses the problem of inanimates being so rarely marked in her corpus that it is statistically questionable to group them with animate objects for a variational analysis, the latter being almost categorically marked.
Experimental approaches seem to be especially useful for the study of DOM because they provide better controlled access to data collection on many of the relevant phenomena. As mentioned above, different experimental paradigms have proven to be applicable and the rate of new publications is increasing. Several papers in this volume present new experimental findings. However, it is still too early to derive more general conclusions from these approaches. Even for acceptability judgments, which are the most frequently used technique, the experimental designs and stimuli differ considerably, and the degree to which particular choices affect participants' ratings has not yet been assessed. It is well known that the choice of the rating scale, the number of distractors included in the study, the use of written or auditive stimuli, presentation mode, presentation of the same item in different manipulations to one participant, etc., all affect the judgments (Schütze 2016). Since the acceptability experiments on DOM vary strongly in their design choices, we need a comprehensive comparative discussion to understand to what extent such methodological choices affect the outcomes, this in order to compare findings from different experiments. The same, obviously, holds for the other techniques, once there are enough studies available. Furthermore, it is also clear that experimental studies rely crucially on replication. So we have still to see which of the effects found in the studies of this first wave of experiments will be confirmed by future investigations.
While different empirical approaches are being applied to Spanish and the number of studies is growing, the situation is much more precarious for the other Romance languages. The experimental studies on Catalan and Italian published in this volume are pioneer contributions. Despite all the possible improvements and unsolved issues for better empirical procedures mentioned above, empirical studies on other DOM languages should be strongly encouraged and linguists working experimentally as well as corpus linguists interested in those languages can both profit from the experiences reported in the development of the methods for the investigation of Spanish DOM.

The contributions to this volume
The first study is a text which might serve as an opening statement for the whole volume: a personal statement by Georg Bossong on the genesis of the term and the concept of Differential Object Marking. Bossong explains how the personal experience of comparing Spanish and Hebrew and the striking similarities between Hebrew et and Spanish a as object marker led him to recognize DOM as a more general phenomenon. The subsequent discovery of parallel elements in different Semitic languages (Aramaic, modern Arabic dialects, Akkadian, Classical Ethiopian) and in typologically very distant languages like Persian and Guaraní inspired him to dub this phenomenon Differential Object Marking, a term first introduced at the end of the 1970s. Bossong offers a list of arguments illustrating the fascinating nature of DOM, and gives several examples of characteristics of DOM in very different languages of the world. Chantal Melis' article "From topic marking to definite object marking. Focusing on the beginnings of Spanish DOM" is based on a broad review of the typological literature on DOM. After laying out the various theories on the origins and grammaticalization paths of DOM, she assesses them with regard to their relevance for the history of the phenomenon in Spanish. Drawing heavily on examples taken from the Cantar de Mio Cid, Melis presents Spanish DOM as originating from topicalization, gradually evolving into a marker of prominence and individuation, before grammaticalizing to become primarily a marker of human objects. In light of the historical evidence provided, other motivations for DOM, such as convergence with the homonymous dative marker or its use as a strategy to resolve syntactic ambiguity, would play at most a secondary role.
Alessia Cassarà/Sophie Mürmann investigate instances of DOM in colloquial Italian, pointing out that Italian is generally not considered to be a DOM language. Based on observations in the literature, they investigate the use of a-marking with object-experiencer psych-verbs in left-dislocated structures and different referring expressions used as direct objects. Their hypotheses are based on García García's (2014) extension of Dowty's proposal of thematic macro-roles. They report an acceptability study conducted with speakers from Northern Italy in which they tested the aforementioned factors. The findings largely support their hypotheses -left-dislocated object-experiencer verbs are the most acceptable verb class tested with a DOM marker, and pronominal objects are favoured over proper names and definite NPs. A surprising finding, namely that indefinite NPs with a generic reading are even more acceptable than all other referential expressions, is explained by assuming that generic NPs are more similar to proper names and that sentences with such expressions might be easier to accept in an out-of-the blue judgment.
Elisabeth Mayer/Liliana Sánchez provide a qualitative and quantitative analysis of corpus data which they collected during fieldwork in bilingual communities in the Peruvian Andes and Amazonas regions and compare them with longitudinal data from monolingual speakers in Lima. They argue for different emerging DOM patterns of clitic-doubling and dislocated structures in the Spanish varieties spoken by these communities, depending on the configuration of the morphology in the given contact languages. These languages are Huánuco Quechua, Asháninka and Shipibo and arguably lead to different preferences that can be captured by aligning the properties of the object NPs on differently arranged scales. The relevant features, it is argued, are definiteness, animacy, patient and theme. According to the authors, it is easier for speakers of Huánuco Quechua than for those of the Amazonian languages to acquire the patterns of DOM and clitic doubling in Spanish, hence the much more frequent occurrence of DOM in their production, which is also much more similar to that of monolingual speakers. The authors also mention other factors which seem to influence the contact varieties, such as the more nuanced marking of thematic roles in Asháninka and the lack of a definite determiner in Shipibo. However, they also note that these differences do not block the acquisition of DOM in clitic doubling structures but rather lead to different results, depending on the feature pool to which speakers of a certain contact scenario have access.
Albert Wall/Philipp Obrist present an elicitation experiment with highly comparable data for six DOM-sensitive configurations in four varieties. They investigate the variation of DOM in Cusco, where Spanish is in contact with Quechua, and in Misiones, where Portuguese and Guaraní are contact languages. The data from the contact varieties are compared with data from predominantly monolingual speakers from Lima and Montevideo. Their results suggest that the different contact scenarios had different effects on the DOM system of the speakers from those regions. While Quechua L1 speakers from Cusco show a rather rudimentary DOM system in general, Misiones differs from predominantly monolingual varieties in terms of greater inter-speaker variability. The study highlights the importance of collecting controlled and comparable data for DOM in comparative studies and shows that different constructions need to be treated differently in quantitative studies, because even superficially very similar sentences may produce very different rates of a-marking.
The contrastive study by Alina Tigău discusses the main commonalities and differences of DOM in Spanish and Romanian, focusing in great detail on syntactic as well as semantic questions, such as specificity, scope, small clause complements and object control, among others. It is shown that marked DOs behave similarly, whereas major differences can be found in unmarked DOs. In light of these findings, it is proposed that the two languages differ in the setting of a parameter which is sensitive to the syntactic type of the direct object: in Spanish, a crucial distinction between KPs and DPs is made, whereas in Romanian the distinction is between KPs and DPs on the one hand and "smaller" nominals on the other. Following López (2012), this distinction is related to the availability of scrambling for the respective nominals. Furthermore, the author concludes that in Spanish, DPs, as well as NumPs and NPs, can incorporate into the verb, whereas in Romanian DPs cannot do so.
In his paper, Niklas Wiskant discusses various proposals that seek to unify a-marking of objects, the distribution of null objects, and leísmo under the same label of Differential Object Marking, using data from Spanish and Portuguese. While both the distribution of null objects and leísmo have been associated with DOM separately, this had not previously been done for the three phenomena together. The author argues that the three phenomena are all based on the same semantic scale and hence proposes to subsume them under the label scalebased object marking. This scale-based object marking is argued to be typical of Ibero-Romance DOM.
Anna Pineda's contribution departs from the normative view on Catalan since the early 20 th century, confronting the prescriptive view with a historical analysis of data from the Corpus Informatitzat del Català Antic, from the earliest written medieval Catalan texts to those of the 16 th century. She shows that the norms propagated by Pompeu Fabra in the first half of the 20 th century contrast not only with what can be observed in spoken Catalan but even with Fabra's own description of the language. His view attributes the strong presence of DOM in spoken Catalan to the influence of Spanish and considers it to be erroneous in several cases. DOM is only tolerated for clear disambiguation. Pineda's detailed analysis of diachronic data shows that DOM cannot be ascribed exclusively to the influence of Spanish. If present at all, this influence has more quantitative than qualitative effects: the contact language acts, in those periods and regions where its influence increases, as a catalyzer for DOM. DOM is already present in Old Catalan, but increases substantially in the 16 th century, when Spanish influence is attested. The detailed analysis shows, among other things, that it is not only important to distinguish diatopic biases in a historical corpus analysis, but that even the level of the individual text can be relevant: the strong relative weight of a 15 th -century Valencian chivalric novel in the corpus, with few occurrences of DOM, has a potentially distorting effect on the overall picture. Senta Zeugin's paper also takes its starting point in the apparent mismatch between the denial of an autochthonous Catalan DOM by normative grammar and several descriptive reports on DOM in Catalan dialects. Her contribution, however, is synchronic and experimental, which, in contrast to the limited access to systematically comparable diachronic dialect data, allows for a design that can provide controlled sets of data. She suggests that Catalan DOM be described as an independent phenomenon, paying special attention to variation between four major regions (Central, North-Western, Valencian, Majorcan). The relevant variables for her experimental approach are animacy and, to a minor degree, the syntactic position of the object, both of which are treated in their own experiments. Results reveal that in general, -DOM is equally acceptable with all degrees of animacy, while +DOM is favoured with higher degrees; with humans, +DOM even attains similar scores as -DOM in Majorcan and Valencian. Unsurprisingly, unmarked canonical sentences score better than DOM-marked dislocations. In general, DOM is preferred in topicalized constructions over dislocations to the right, but this preference is significantly more strongly marked in Central Catalan than elsewhere. The author concludes that Catalan DOM appears to resemble (Peninsular) Spanish DOM in the differentiated acceptability of +DOM with different types of objects, while -DOM is, unlike in Spanish, always acceptable. Each step of the experimental design is carefully documented, which makes this article a methodological model of the implementation of claims from the literature in an experimental design.
Diego Romero discusses a possible "global" influence of DOM, the factor of telicity and its impact in DOM in the history of Spanish. His study is based on a diachronic corpus-based analysis with data from the Corpus del nuevo diccionario histórico del español (CDH). Romero filters data from three diachronic cuts (14 th , 16 th and 20 th centuries) through a "telicity test", looking at the telic or atelic verbal aspect and at several properties of the object. Against Torrego's (1999) claim that telic verbs favour DOM and DOM favours a telic interpretation of atelic verbs, no such correlation is confirmed by the analysis of the data; there is, however, a rather weak effect on the subset of indefinite direct objects. Even if the general result is negative and the initial hypothesis is thus not confirmed, the author admits that the apparent correlation between telicity and DOM observed in literature might be an indirect effect of other global influences triggered by the relationship of the semantics of the verb and the object, such as agentivity or affectedness.
The principal hypothesis of Javier Caro Reina/Marco García García/Klaus von Heusinger is that the lower incidence of DOM marking in Cuban Spanish might be the consequence of DOM retraction. Their empirical study is twofold: first, a corpus study based on selected verbal lemmata in CORDE (equally distributed between verbs denoting more or less affectedness), limited to human NPs (both definite and indefinite), examines the evolution of DOM from the 19 th to the 20 th century. Only "canonical" SVO-type sentences were taken into account. Second, a judgment experiment conducted in Cuba and Spain investigates acceptability for both of the aforementioned categories. The authors derive evidence for retraction from two findings: on the one hand, whereas the frequency of DOM in 20 th -century Cuban Spanish is similar to that in 16 th -century European Spanish, according to works of other authors, their own CORDE-based diachronic study shows a decrease in DOM from the 19 th to the 20 th centuries, at least in indefinite NPs. Comparing the CORDE data to Alfaraz's 2011 oral corpus study, the decrease seems even more plausible, assuming that oral registers are less conservative. On the other hand, the acceptability experiment reveals that unmarked human objects are considerably more acceptable in Cuba than in Spain. The gradings mirror DOM expansion, both unmarked definites and unmarked indefinites being more acceptable in Cuba, while there is no dialectal difference for the respective marked conditions. In general, the article raises several methodological questions (complementarity of experimental and corpus approaches, comparability of different corpora). Even within the corpora, inter-author variation is considerable.2

Outlook
In her overview article, Pensado (1985, 19) characterizes the field as a series of pioneering approximations to the phenomenon that deal with similar problems and propose similar solutions, but she regrets the lack of a common ground for research on DOM. She expresses the hope that in future work, once the different proposals are "unified in a critical perspective", there will be a major advance in knowledge. With regard to methodological innovations thus far, it still seems accurate to say that there is a lot of pioneering work towards approximation, but 2 Most of the papers presented in this book are revised versions of contributions to a symposium held in Zurich in summer 2018. We would like to thank the Swiss National Science Foundation for its generous support. Thanks also to the anonymous reviewers for their useful comments and to John Barlow, Barbara Reynoso and Larissa Klose for proofreading and preparing the manuscript. that a full convergence of results is still out of reach. However, despite the lack of a unified account, we observe the accumulation of knowledge through empirical work with different data types. New problems are being identified, and proposals for solutions are being developed. Hence, it seems that an accumulation of knowledge is possible even before the big unifying breakthrough. It may in fact be necessary first to build up a more solid foundation of knowledge with different data types that can compensate for the shortcomings of each other in order to complete the picture of what the unifying proposal might ultimately look like.