Phonetic convergence to Southern American English: Acoustics and perception.

Phonetic convergence is linguistically and socially selective. The current study examined the constraints on this selectivity in convergence to Southern American English by non-Southern Americans in a word shadowing task. Participants were asked either to repeat the words after the model talker, to repeat the words after the model talker from Louisville, KY, or to imitate the way the model talker from Louisville, KY, said the words, in a between-subject design. Acoustic analysis of the participants' productions revealed significant phonetic convergence on word duration and back vowel fronting, but not on /aɪ/ monophthongization, across all three instruction conditions. These findings suggest social selectivity such that convergence on stereotyped variants is avoided, but convergence to a talker with a non-prestigious variety is not. A perceptual assessment of convergence confirmed the acoustic results, but also revealed significantly more convergence in the explicit imitation condition than in the two repetition conditions. These findings suggest that explicit instructions to imitate lead to greater convergence overall, but do not completely override social selectivity. A comparison of the acoustic and perceptual assessments of convergence indicates that they provide complementary insights into specific features and holistic patterns of convergence, respectively.

Relative Contributions of Social, Contextual, and Lexical Factors in Speech Processing.

This exploratory study examined the simultaneous interactions and relative contributions of bottom-up social information (regional dialect, speaking style), top-down contextual information (semantic predictability), and the internal dynamics of the lexicon (neighborhood density, lexical frequency) to lexical access and word recognition. Cross-modal matching and intelligibility in noise tasks were conducted with a community sample of adults at a local science museum. Each task featured one condition in which keywords were presented in isolation and one condition in which they were presented within a multiword phrase. Lexical processing was slower and more accurate when keywords were presented in their phrasal context, and was both faster and more accurate for auditory stimuli produced in the local Midland dialect. In both tasks, interactions were observed among stimulus dialect, speaking style, semantic predictability, phonological neighborhood density, and lexical frequency. These interactions revealed that bottom-up social information and top-down contextual information contribute more to speech processing than the internal dynamics of the lexicon. Moreover, the relatively stronger bottom-up social effects were observed in both the isolated word and multiword phrase conditions, suggesting that social variation is central to speech processing, even in non-interactive laboratory tasks. At the same time, the specific interactions observed differed between the two experiments, reflecting task-specific demands related to processing time constraints and signal degradation.