The first part of this article investigates the distribution and emergence of
front rounded vowels (FRV) in the Portuguese dialect spoken on the Azorean
island of São Miguel in light of data taken from the Ethnolinguistic Atlas of
the Azores (ALEAç). The analysis confirms previous findings about the
distribution of FRV. Additionally, the ALEAç shows that this phenomenon
spreads beyond the well-known contexts of stressed positions. FRV also occur
in unstressed syllables and the mid-front rounded vowel [ø] alternates with
its diphthongised counterparts [øj] and [øw]. This alternation calls for a
reflection about the historical and articulatory background of [ø] in
Portuguese dialects. The extensive use of FRV opens up further research
perspectives in terms of the sociolinguistic significance of the phenomenon.
The second part of this article focuses on the sociohistorical background of
the emergence of FRV in Portuguese dialects. The concept of the feature pool
provides a framework for the processes of feature selection in a situation of
linguistic contacts such as those preceding the settlement period of the
Azores and subsequent contact on the islands. A combination of three different
concepts of markedness helps understand why a highly unusual feature like FRV
emerged and persists until today
