Colloquium: Eleanor Chodroff

Linguistics Department Colloquium:

Eleanor Chodroff (Postdoctoral Fellow, Northwestern University)

Uniformity in phonetic realization within natural classes

The phonetic realization of a given speech sound varies substantially across languages and across talkers within a language. While many factors contribute to this variation (e.g., sociolinguistic, physiological), there is considerable evidence that phonetic variation is highly structured among speech sounds. Structured variation of this type can be observed in the covariation among vowels in the F1xF2 vowel space, as talkers form relatively congruent, but shifted vowel spaces (e.g., Joos, 1948; Nearey, 1978), as well as in the covariation of talker mean voice onset time among aspirated stop consonants (e.g., Chodroff & Wilson, 2017). The presence of covariation reveals constraints on permissible variation in language- and talker-specific sound systems (e.g., Liljencrants & Lindblom, 1972), and may be exploited in generalized perceptual adaptation to novel talkers.

In this talk, I will examine two primary constraints on the phonetics-phonology interface that could give rise to covariation across talkers. These constraints are formalized as target uniformity, which requires similar (or identical) phonetic realization of a distinctive feature value within a talker, and contrast uniformity, which requires a comparable phonetic difference in sounds that contrast in a feature across talkers. Evidence from variation in sibilant fricatives implicates target uniformity, but not necessarily contrast uniformity as a constraint on phonetic realization. The universality of target uniformity on the phonetics-phonology interface will also be considered in several case studies of stop VOT which include cross-linguistic, bilingual, and child speech data.

An overarching principle of uniformity that governs the mapping from phonological to phonetic representation may account for strong, structured relations among speech sounds in the output. This constraint should therefore be included alongside principles of perceptual distinctiveness and articulatory ease when considering factors that shape the phonetic instantiation of individual speech sounds.