SUMMARY
This study aims at examining the occurrence and direction of any phonetic interlanguage interference among Yemeni Arabic-English bilinguals by indicating the acoustic similarities and differences of L1 Yemeni Arabic stops produced by bilinguals and comparing it to monolinguals. It investigates Voice Onset Time of stops in initial and medial position as well as Preceding Vowel Duration of stops in medial position. A total of 60 native Yemeni Arabic subjects were involved in this study. Thirty subjects were late bilinguals with English as their L2 whereas the other 30 were monolinguals. Data was collected through two production tests: one for the bilingual group and the other for the monolingual group. All the subjects were asked to produce a list of Arabic words with the target stops /b, t, d, k/ in word-initial and word-medial position. Each subject in both samples was recorded individually. The bilingual subjects showed significantly longer mean Voice Onset Time values than monolinguals for /t, k/ whereas they showed mean Voice Onset Time values for the voiced stops /b, d/ that were very close in values to the monolingual group. However, bilinguals showed shorter mean values than monolinguals for the Preceding Vowel Duration, but the difference was not significant. The findings reveal that bilinguals showed signs of English-induced L1 phonetic drift in their pronunciation of Arabic /t, k/ whereas not in their realisation of Arabic /b, d/. This study provides conclusive evidence that L2 characteristics can systematically affect matured L1 phonological systems even among late bilinguals.