Place uniformity and drift in the Suzhounese fricative and apical vowels

Suzhounese exhibits an unusual place anteriority contrast between rounded and unrounded dorso-palatal high front vowels, postalveolar fricative vowels, and apico-alveolar apical vowels. This arrangement is vulnerable to loss under intensifying contact with Standard Mandarin. Using acoustic and tongue ultrasound data, we investigated the phonetic implementation of place in the Suzhounese fricative and apical vowels and the similarity of place targets with the apico-alveolar and alveolo-palatal fricative consonants /s/ and /E/, and the front vowel /i/. Two age cohorts differing in their acquisition history and usage of Standard Mandarin were investigated. The younger cohort, who had earlier and likely more intense exposure to Standard Mandarin, exhibited a subphonemic shift in the fricative vowels toward less anterior, more /i/-like constrictions. Due to this shift, implementation of place targets among vowels and consonants was less uniform for the younger cohort, particularly in acoustic terms, but articulatory target uniformity among the vowels at each place was robust for both cohorts regardless of the degree of shift. We discuss possible contact-based mechanisms for the observed changes, as well as implications of the observed interactions between L1-L2 transfer and L1-internal structural cohesion.