An acoustic examination of English fricative production by Korean- and Farsi-English bilinguals: The role of language- and orthographic-specific effects

Abstract

Recent work has shown that exposure to orthographic effects can promote first-language (L1) phonological transfer. However, it is relatively unknown whether orthographic effects persist in highly proficient bilinguals. Here, we examined how L1 orthographic depth (regularity in grapheme-phoneme correspondences) modulated Korean-English and Farsi-English bilinguals’ (n = 25 each) production of fricatives in English words (e.g., <mellow> /ˈmeloʊ/ vs. <melon> /ˈmelən/). Native English speakers (n = 25) served as a control group. Because fricatives are produced as geminate sounds in both Korean and Farsi, we expected L1-based transfer. Participants completed four tasks: an eye-movement reading task, word-naming task, cloze test, and language background questionnaire. The stimuli were controlled for word frequency, word length, number of syllables, and stress. We expect language-specific differences, corroborating previous neuro-linguistic evidence that shallow and deep orthographies differentially rely more heavily on phonological and lexical pathways, depending on language-specific demands. To explore this aspect, we employed an acoustic classification method for fricatives extracting cepstral coefficients and using HMMs to divide the sounds in regions based on their internal variance, aimed at determining whether fricatives produced by different groups can be classified correctly. This work has implications for both second-language (L2) speech learning models and classroom instruction.