Electronic Thesis and Dissertation Repository


Master of Science




Marc Joanisse


Research investigating the neural correlates of second language (L2) processing has usually studied age of acquisition (AoA) and proficiency separately. Presently, we examined both in parallel, treated as continuous variables. We used fMRI to study neural activity for L2 processing in adult native Mandarin speakers who are L2 English speakers. Behavioral measures of language proficiency and AoA were obtained from subjects prior to performing a picture-word matching task during an fMRI scan. Brain activity during L2 English processing was shown to be independently affected by AoA and proficiency; activity in left superior temporal gyrus and right parahippocampal gyrus was modulated by AoA when L2 proficiency is accounted for, while activity in right insula, right middle temporal gyrus, and left parahippocampal gyrus was modulated by L2 proficiency regardless of AoA. These results suggest that brain organization of L2 lexico-semantic processing is susceptible to L2 ability levels as well as age-dependent learning.