One explanationto this problem is the negative transfer or interference from the learners’ L1feature which is really different from the L2. (Yule, 1996, p.194-195) This means they transfer the sound feature of their native language into English. As Jinkins (2000, p.39) explained that comprehensibility in English relies enormously on word stress, and since the feature is highly rule-governed, language learners inevitably have problems in acquiring these rules, particularly where the rules of L1 are both different and less complicated. In addition, the study of word stress in Thai, conducted by Peyasantiwong (1986,p.211), indicates that the role of stress is the most prominent, or has strong stress on the syllable in word-final position. On the contrary, the English word stress is much less predictable. It has a reputation of being complex, difficult to deal with because its primary stress can appear in any syllable positions of a word. (Roach, 2000, p.97) As a result, most Thai learners are likely to put the main stress on the final syllable of a word due to the L1 interference. 

How can we find a solution to this problem? The answer is surprisingly interesting when I have found phonetics and phonology provide well-established understandings of sound patterns of English. The rules of word stress in English are much more objective than I ever knew before. Despite no exact rules for determining word stress, these systematic rules are very beneficial for English language learning and teaching. They include 1) word stress can be characterized into three levels: primary, secondary, and weak, but the primary stress is the most significant one. 2) two-syllable words generally receive the primary stress on the first syllable. 3) for noun/verb pairs, the noun usually has the primary stress on the first syllable while the verb has the primary stress on the second syllable. 4) the primary stress is also controlled by stress-controlling suffixes. Words ending with suffixes such as -oon, -ee, -eer, normally have primary stress, while words ending with suffixes such as -ical, -ious, -ion, -ity, -logy and so on generally have primary stress on the syllable before them. Last but not least, 5) the primary stress never occurs in the position of short-vowel syllables such as /i/. As an English teacher, I can use these facts to design my lesson plans or teaching materials in a more creative and productive way.

However, I think that pronunciation teaching of English word stress in Thai educational context has received very little attention from ELT scholars. Being knowledgeable about the rules may not be sufficient for the teacher to teach effectively. Any research findings would provide solid evidence on how the teaching of word stress could be structured and organized. Therefore, more classroom-based researches on this area of study should be supported.

References:

Jenkins,J. (2000). The Phonology of English as an International Language.Oxford: Oxford University Press.

Peyasantiwong,P. (1986). Stress in Thai, in A Conference on Thai Studies in Honor of William J. Gedney, ed. R.J. Bickneretal.,Ann Arbor, Michigan.

Roach,P. (2000). English Phonetics and Phonology. (3^rd ed.). Cambridge: Cambridge University Press.

Yule,G. (1996). The study of language (2nd ed.). Cambridge: CambridgeUniversity Press.