Lee, Goun. 2018. Effect of word frequency in producing English unstressed vowels by Korean learners of English. Studies in Phonetics, Phonology and Morphology 24.2. 193-208. 

The current study aimed to investigate whether Korean L2 learners of English can acquire vowel reduction cues to stress as their English proficiency increases, and whether lexical frequency influences on the acquisition of vowel reduction. Fifteen Korean learners and 15 English speakers produced 13 English disyllabic stress minimal pairs (e.g., OBject – obJECT), adopted from Lai (2008). F1 and F2 values of the first syllables were measured and compared according to the stress patterns (first syllable stressed vs. second syllable stressed). The results showed that English proficiency cannot predict vowel reduction to stress for Korean L2 learners. However, word frequency showed a significant effect on the production of unstressed syllables from English native speakers as well as Korean learners of English, suggesting that high frequency words undergo more reduction than low frequency words. Taken together, these findings demonstrated that the difficulty in producing vowel reduction might be due to the difficulty in learning articulatory gestures, rather than to the dissimilarity of phonological features between L1 and L2. (Sungkyunkwan University, Lecturer)

Keywords: English lexical stress, Vowel reduction, Word frequency