An Empirical Study Of Phonetic Transfer In English Monophthong Learning By Tibetan (Lhasa) Speakers

English teaching has been carried out in every region of China. However, the teaching of English phonetics in minority regions faces the problems of poor teaching quality and low intelligibility of phonetic production. For most students from minority regions, L1 is the native language, with Chinese as L2 and English as L3. Given the differences and similarities among the three languages in their vowel systems, such a learning process may lead to the phonetic transfer of L1 and L2 on L3 in the process of L3 vowel learning.Under the framework of Speech Learning Model(SLM), the current research adopts the experimental phonetic approach to examine the characteristics of the vowel space of 10 Lhasa students'(5 male and 5 female) English in continuous speech, with a purpose to explore minority students' phonetic transfer of L1 and L2 on L3 vowel system. Compared with Standard Southern British English pronunciation(SSB)(Deterding, 1997), English by Lhasa students presents the following features: 1. Both Tibetan male and female speakers cannot distinguish English long and short vowels(/i:/-/?/, /e/-/?/, /?/-/?:/, /?/-/?:/, /?/-/u:/). 2. The acoustic features of /?:/, /?/, /?/, /?/ and /?/ by Tibetan male speakers are closer to those of SSB. 3. The acoustic features of /e/, /?/, /i:/, /?/ and /?/ by Tibetan female speakers are closer to those of SSB.Euclidean distance between Tibetan speakers' English and Tibetan, and Tibetan speakers' English and Chinese reveals the degree of phonetic transfer of Tibetan(L1) and Chinese(L2) on English(L3). The results show that due to equivalence classification, the production of the English vowel /?:/ is more influenced by the Tibetan counterpart /a/, and the productions of English vowels /i:/ and /?/ are more influenced by the Tibetan counterpart /i/. Moreover, the productions of English vowels /?/ and /u:/ are more influenced by the Chinese counterpart /u/, and the production of Tibetan female speakers' /?:/ is more influenced by the Chinese counterpart /?/.The study has revealed that the nonstandard English vowel production by Lhasa students is due to the influence of the similar vowels in L1 or L2. The results have partly confirmed SLM's hypothesis that category formation for a target language sound may be blocked by the mechanism of equivalence classification. Lhasa students' English vowels /?:/, /i:/ and /?/ are more influenced by Tibetan similar vowels, and their English vowels /?/ and /u:/ are more influenced by Chinese similar vowels. In addition, Tibetan female speakers' /?:/ is more influenced by the similar vowel in Chinese. All of this indicates that when Tibetan speakers learn L3, the interference seems to be partly from their L1 and partly from their L2. Therefore, in minority students' L3 vowel learning, both L1 and L2 have influence on their L3 vowel system. The present research can help strengthen phonetic teaching among ethnic minorities and provide more effective empirical data for speech synthesis and speech recognition of ethnic minorities' English.