Linguistically Informed Acoustic and Perceptual Analysis of Bilingual Children's Speech Productions: An Exploratory Study in the Jamaican Context

Purpose: The aim of this study was to characterize speech acoustics in bilingual preschoolers who speak Jamaican Creole (JC) and English. We compared a standard approach with a culturally responsive approach for characterizing speech sound productions. Preschoolers' speech productions were compared to adult models from the same linguistic community as a means for providing confirmatory evidence of typical speech patterns specific to JC-English speakers. Method: Two protocols were applied to the data collected using the Diagnostic Evaluation of Articulation and Phonology (DEAP) Articulation subtest: (a) the standardized DEAP protocol and (b) a culturally and linguistically adapted protocol reflective of the Jamaican post-Creole (English to Creole) continuum. The protocols were used to analyze responses from JC-English-speaking preschoolers (n = 119) and adults (n = 15). Responses were analyzed using acoustic (voice onset time, whole-word duration, and vowel duration) and perceptual (percentage of consonant correct-revised and response frequencies) measures. Results: The culturally responsive protocol captured variation in the frequency and acoustic differences produced in the post-Creole continuum, with higher amounts of "other" responses compared to "standard" target responses for both children and adults. Adults' whole-word durations were shorter and showed more consistent prevoicing during initial plosives compared to the children. Conclusions: Applying culturally responsive methods, including knowledge of the variation produced in the post-Creole continuum and with adult models from the same linguistic community, improved the ecological validity of speech characterizations for JC-English preschoolers. Acoustic properties of speech should be investigated further as a means of describing bilingual development and distinguishing between difference and disorder.