Effect of Linguistic Similarity on Second Language Processing: An fMRI study
Hyeonjeong Jeong
Graduate School of International Cultural Studies, Tohoku University, Sendai, Japan

Abstract:
In this study of native speakers of Korean, we examined the effect of syntactic similarity between first and second languages on cortical activation during the processing of Japanese and English, which are respectively very similar to, and different from, Korean. Subjects had equivalent proficiency in Japanese and English. They performed auditory sentence comprehension tasks in Korean, Japanese, and English during functional magnetic resonance imaging. We found significantly greater activation in the bilateral superior temporal cortex during the comprehension of Korean, English, and Japanese. The pars triangularis of the left inferior frontal gyrus was additionally activated for second language processing. Furthermore, we found significant activation in the right cerebellum, the pars opercularis of the left inferior frontal gyrus, and the posteriomedial part of the superior frontal gyrus during the English sentence comprehension task only. Significantly greater activation was found in the pars opercularis of the left inferior frontal gyrus, the right cerebellum and the right superior temporal cortex during the English than Japanese sentence comprehension tasks; activation in these regions did not differ significantly between Korean and Japanese tasks. Differential activation of the pars opercularis of the left inferior frontal gyrus and the right cerebellum likely reflects syntactic distance between and differential activation in the right superior temporal cortex may reflect the prosodic distance between English from Korean and Japanese. Furthermore, in the pars oparcularis of the left inferior frontal gyrus and the right cerebellum, significant negative correlation between the activation and duration of exposure was observed for English, but not for Japanese. Our research thus supports the notion that linguistic similarity between first and second languages affects the cortical processing of second language. That is, when second language is typologically similar to first language, the shared syntactic system may allow second language processing to draw on efficient neural system for first language, exempting the effect of the amount to exposure.