Stressed vowel assimilation to palatal consonants in early Romance

This study is an investigation of the phonetic causes of stressed mid and low vowel raising and diphthongization before single palatal consonants and [jC] sequences in the Early Romance languages, as for example [a] raising in Spanish leche derived from Latin [ˈlakte] ‘milk’. The initial hypothesis put to test is that the chances that vowel assimilation applies should increase with the prominence of the anticipatory consonant-to-vowel effects in tongue dorsum raising and fronting and in the second formant (F2) frequency. In accordance with this prediction, vowel assimilatory processes were found to operate most often before [j] + dentoalveolar sequences and single palatals involving maximal dorsal contact in the case of [a] (and to some extent for [ɛ ɔ] as well), and before single palatals rather than before consonant sequences with [j] in the case of [o]. Moreover, assimilation was more prone to affect [ɛ a ɔ o] than the mid high front vowel [e]. The phonetic account of vowel raising and diphthongization reported in the present study complements other explanatory proposals based on chronological and etymological factors. It also supports the notion that the categorization of segmental coarticulatory effects as assimilatory increase with coarticulation size, and that the diachronic vowel changes in question occurred at a time when palatal consonants were in the process of gaining stability.