The Influence of L1 Phonological Features on the Perception of Voicing-conditioned Vowel Length Differences in English by Mongolian Learners of English

The main purpose of this study is to determine whether Mongolian learners of English as a second language can perceive English minimal pairs that shows voicing contrast in word-final positions. In English, the length of the preceding vowel changes depending on the presence or absence of voicing in the following consonant, which is understood as a significant phonological phenomenon in English. Given that voiced sounds become voiceless at the end of words, voicing contrast is neutralized. Therefore, the difference in the length of the preceding vowel is a more important perceptual cue than word-final voicing contrast in English. Noticing that Mongolian vowels have a phonemic contrast between short and long vowels, we realize that vowel length is a phonological feature in Mongolian. In terms of second language acquisition, it can be predicted that Mongolian learners will easily acquire English vowel length difference due to the fact that vowel length is a phonological feature in L1 grammar. In this study, I conducted two types of speech perception tasks with 25 Mongolian participants as an experimental group and 25 native speakers of English as a control group: AX-discrimination and identification tasks. In the AX-discrimination task, Mongolian participants performed as well as native English speakers, which seems to support the positive transfer effect of L1 grammar on L2 perception. On the contrary, Mongolian participants showed much poorer performance than English speakers in identifying the corresponding word that they listened to from a series of minimal pairs. It can be assumed that Mongolian learners did not learn voicing-conditioned vowel length in English. Crucial to the findings of the study is that learners need to understand phonological phenomena in L2 in order to correctly perceive L2 phonemes even though L1 phonological features can be helpful in distinguishing phonetic differences in L2.