Abruzzese, a southern Italian variety spoken in the central Italian region of Abruzzo, makes use of an impersonal pronoun, nomə , which is the continuation of Latin hŏmo (D'Alessandro & Alexiadou 2006). Nomə is used both as an arbitrary 3rd person pronoun and as a generic pronoun. Its use was quite widespread in the Abruzzo and Molise regions until about 50 years ago; however, as a result of heavy contact with Italian, it has recently been almost completely abandoned, and appears to be used only by the older generation of speakers. Its function has also been reshaped, in that it mostly serves as a marker of plurality on verbs. The loss of impersonal pronouns is a common trend in the European area, as witnessed by the typological study conducted by Giacalone Ramat & Sansò (2007). This typological trend, particularly combined with the significant decay of the dialects in favor of a generalized use of regional Italian, means that the creation of new impersonal pronouns is wholly unexpected. However, it appears that a new impersonal pronoun, annə , is in fact emerging in Abruzzese, and is almost entirely replacing nomə in most areas of Eastern Abruzzo. The development of this impersonal pronoun is following a rather unusual path, seeming to be the result of the re-adaptation of an auxiliary borrowed from Italian. This paper examines the diachronic development of both pronouns, showing that they follow opposite paths. While nomə is grammaticalizing into a plural marker, annə is degrammaticalizing into an arbitrary pronoun.