Abstract
Middle and Upper German dialects exhibit a phonological process of s-retraction neutralizing alveolar [s] to palatoalveolar [ʃ] in preconsonantal contexts. Based on a corpus of dialect data from own fieldwork, dialect atlases and dictionaries, we examine this process in Germanic, Romance and Slavic varieties of the Eastern Alps. It is attested in most Germanic varieties and in Ladin and Rumantsch, but not in other Romance varieties or in the Slovenian dialects of the region. We propose that the emergence of s-retraction may be supported by language contact, but crucially relies on specific diachronic changes affecting the sibilant inventories of the varieties displaying it.