A functional MRI was used to investigate the computational neuronal model of differential processing patterns of two languages (Korean as a mother language, L1 and English as L2) in the late Korean-English bilingual subjects during the performance of a Stroop task during overt production of words. The Stroop paradigm experiment was done separately in L1 and L2 and the imaging results of these different conditions were compared. In the case of L1, the activation of the bilateral anterior cingulate gyrus was observed among others. L1 related activation was also observed in middle frontal and inferior parietal lobule. In the case of L2, frontal and parietal as well as superior temporal activation was observed, but the absence of ACC activation was reported. This difference led to an argument that the differential information processing (automatization, inhibition control) mechanisms between L1 and L2.