Phonetic Reduction of English Function Words in the Passage Reading by Korean EFL Learners

This paper investigates how Korean EFL learners, whose L1 does not reduce function words, reduce vowels in the production of English function words in comparison to native speakers of English. Specifically, the degree of reduction of function words was investigated in terms of their subclasses, that is stressed (strong) and unstressed (weak) function words in comparison to content words. To this end, 54 speakers (20 Korean male, 20 Korean female, 7 American male, and 7 American female) were recorded and measured in terms of acoustic features, F0, duration, and intensity in the reading of a passage with 11 sentences. The results revealed that both American and Korean speakers produce stressed function words that are significantly longer in duration than unstressed function words, supporting the argument for the existence of subclasses of function words. Korean female learners tend to overemphasize stressed function words, which results in an insignificant difference in duration between content words and stressed function words, while the reverse pertains in terms of intensity (i.e., stressed function words are greater in intensity than content words). Secondly, vowels in the unstressed function word class were reduced homogeneously by native speakers, but variably in the readings of Korean learners. Finally, modals were reduced more than finite auxiliaries by all the groups, which contradicts the stressability order between morphemes proposed by Anttila (2013). This study provides evidence for the subclass effect on stress realization by Korean EFL learners, as well as native speakers. The findings also have some teaching implications for EFL students.