Bilingualisam and the relationship between perception and production : Greek-English bilinguals and Thai bilabial stops

This study investigates two issues: the effect of bilingualism (Greek/Australian-English) on speakers' ability to perceive unfamiliar speech contrasts (in this case Thai); and whether speakers' speech productions bear any relationship to their speech perception. Thai has three bilabial stop contrasts in word-initial position, voiced /b/, voiceless /p/ and voiceless aspirated /ph/. English and Greek both have two-way voicing distinctions, voiced /b/ and voiceless /p/, but in the wordinitial position in English, /p/ is realized as an aspirated [ph] and only occurs as an unaspirated [p] when in other than the initial position. Experiment 1 examined the perception of Thai bilabial stops by monolingual Australian-English speakers, bilingual Greek/Australian-English speakers, and a control group of Thai speakers. Experiment 2 examined the production of bilabial stops by these speaker groups. The results of Experiment 1 show no difference between the three speaker groups when discriminating the Thai distinctions /ba/ versus /pha/ and /pa/ versus /pha/. However, there was a tendency for Greek/Australian-English speakers to discriminate /ba/ versus /pa/ better than monolingual English speakers. More importantly, when participants were classified on the basis of their production profiles obtained in Experiment 2, Greek/Australian-English speakers with extreme voice onset times for /ba/ and /pa/ productions showed comparable perceptual performance to that of the Thai speakers. These results suggest that bilinguals who exaggerate the voicing differences between sounds when speaking, best perceive these differences when listening. These findings show that production profiles are an important adjunct to the assessment of bilingual speakers, and have important implications for the interface between perception and production.