One head, two languages : speech production and perception in Greek-English bilinguals

The way that bilinguals produce and perceive phonetic contrasts in each of their languages is thought to provide a window into the nature of the bilingual phonological space. Research has demonstrated that bilinguals usually show a persistent influence from their native language (L1) on the second language (L2) for both speech production and perception, but it has been suggested that bilinguals who are L2-dominant are the most likely to suppress this L1-interference. In addition, theories of bilingual language activation and inhibition posit that the situational language context biases bilinguals to select language-specific information when using their two languages; we extend this concept to address bilingual speech production and perception. Specifically, this thesis examined the production and perception of stop consonant voicing contrasts by L2-dominant bilinguals in opposing L1 or L2 language contexts. Greek–English bilinguals were chosen because Greek and English differ in their phonetic settings for stop-voicing distinctions, allowing for objective comparisons between mono- and bilinguals, and for quantifying any L1-L2 interaction effects. In production, bilinguals matched monolinguals in Greek (L1) across all phonetic contexts tested, although English (L2) productions in complex medial contexts showed an L1 influence. In a codeswitching experiment, in which both languages were engaged, this L1-interference on L2 productions was exacerbated. Therefore, it appears that L2 dominance does not guard against an L1 influence on production of L2. In perception, bilinguals showed a strikingly different pattern of L1-L2 interaction: they were sensitive to L1 and L2 realisations of the same phoneme in categorisation and rating judgments about stop voicing, yet their discrimination was heavily biased toward their dominant L2 (English). Overall, the results are interpreted as indicating that bilinguals integrate both languages in a common phonetic space, swayed by their long-term dominant language environment, but they can selectively attend to language-specific phonetic information for phonologically-motivated judgments (category-goodness ratings). It is argued that the asymmetry observed between speech production and perception is a result of the bilinguals’ unique language learning histories and differences in communicative pressure in the domains of speech perception and production