Date of Award

August 2015

Degree Type


Degree Name

Doctor of Philosophy



First Advisor

Hanyong Park

Committee Members

Anne Pycha, Garry Davis, Jae Yung Song, Sandra Pucci


Phonetics, Psycholinguistics, Speech Perception Training






Siriporn Lerdpaisalwong

The University of Wisconsin-Milwaukee, 2015

Under the Supervision of Professor Hanyong Park

Many studies have revealed that ESL and EFL Thai leaners have difficulty producing and perceiving certain English consonants and vowels. The difficult consonants are /b d g v θ ð z tʃ ɹ l/ (Burkardt, 2005; Francis & McDavid, 1958; Jotikasathira, 1999; Lerdpaisalwong & Park, 2012, 2013; Richards, 1968; Wei & Zhou, 2002). The difficult vowels are /ɪ i ʊ u/ (Richards, 1968; Tsukada, 2009; Varasarin, 2007). Previous studies have showed that laboratory perceptual training using highly variable naturally produced stimuli (HVNP) can improve L2 learners’ perceptions (e.g., Lively, Logan, & Pisoni, 1993). Nishi & Kewley-Port (2007, 2008) revealed that such training works even more effectively, with the case of vowel, when both Japanese and Korean L2 learners of English were trained with the fullset (i.e., both easy and difficult segments) of segments investigated, rather than the subset (i.e., only difficult segments) of segments.

This study investigates whether those factors found to be effective in training speech perception together with the training set technique suggested in Nishi & Kewley-Port (2007) also work effectively in training Thai EFLs (N = 32) with English vowels. In addition to perception training on vowels, this study includes perception training on consonants in two different phonological contexts (i.e., onset and coda) and examines how the training set technique works in training Thai EFLs (N = 61) with English onsets and codas. Patterns of both learners’ and segments’ improvement are observed and presented. The generalization of the trained perception abilities to new talkers is also demonstrated.

In line with Nishi & Kewley-Port (2007, 2008), the results of the current study show that fullset training worked more effectively in training Thai EFLs with English vowels. The results, therefore, correspond to the findings from the previous studies and suggest that this technique works well in both ESL and EFL contexts. Interestingly, the results showed similar patterns between vowel and consonant training whereby the fullset training also worked more effectively in training Thai EFLs with consonants (i.e., both onsets and codas), although vowels and consonants vary in many respects. This suggests that there is to some extent a relationship between the acquisition of L2/ target-language vowels and consonants (Best and Tyler, 2007; Bohn and Flege, 1997; MacKain, Best, & Strange, 1981). The results also suggest a linkage between productions and perceptions when compared to the study of Burkardt (2005). Importantly, after going through the training sessions, Thai EFLs in every training group could generalize their trained perception abilities to the new talkers.

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