The effects of neighborhood density and word frequency on the production of English-learning Korean speakers

English vowel production conditioned by probabilistic accessibility of words: A comparison between L1 and L2 speakers*

“…In this respect, our results on vowel lengths, coupled with converging previous data obtained from different sets of words (Kilanski, 2009;Yun, 2010), call for future research on a possibly multi-layered encoding system between probabilistic information indexed at the lexical level-i.e., frequency and density that come into play in an early stage of speech production such as lexical access-and information at the phonological or articulatory leveli.e., phonotactic probability that would wield its influence in the following stage where articulatory gestures are executed.…”

“…Importantly, as an effect of lexical difficulty, the native group's vowels appear to have been realized over a larger hexagonal area when the vowel was contained in a hard word (solid line), compared to when it was in an easy word (dashed line). Also in line with the previous studies (Munson & Solomon, 2004;Wright, 2004;Yun, 2010), the native group's articulatory expansion is less clearly observed for back vowels than front vowels, particularly for /o/, probably due to greater restrictions for retracting the tongue root.…”

“…The L2 group (lower panel) exhibited some noticeable differences from the native group (upper panel). While the native group showed relatively clear separation of spectral qualities between vowel categories, the L2 group showed larger overlaps for the tense-lax contrast between /i/ and /ɪ/, and for back vowels due to their use of a smaller height range in the back cavity, both of which are known as typical patterns of Korean L2-ers' vowel production (Koo, 2000;Yun, 2010).…”

“…While this sort of experience-based view is widely adopted in a variety of literature on phonological processing, the extent to which L2 speakers utilize this mechanism remains unanswered in general. Literature on the influence of English words' probabilistic accessibility is also limited but Yun (2010) explored it, deploying a production experiment with Korean L2 speakers at an intermediate or advanced level. The results showed that realizations of the first two formants were slightly strengthened for words with low frequency or words with high neighborhood density, suggesting L2-ers may also have internalized probabilistically conditioned vowel specificity.…”