The dynamic nature of assimilation and accommodation procedures in the brains of Chinese-English and English-Chinese bilinguals.

The framework of assimilation and accommodation has been proposed to explain the brain mechanisms supporting second language reading acquisition (Perfetti et al. [2007]: Bilingual Lang Cogn 10:131). Assimilation refers to using the procedures of the native language network in the acquisition of a new writing system, whereas accommodation refers to using second language procedures for reading the newly acquired writing system. We investigated assimilation and accommodation patterns in the brains of bilingual individuals by recruiting a group of Chinese-English bilinguals and a group of English-Chinese bilinguals to perform lexical decision tasks in both English and Chinese. The key question was whether the assimilation/accommodation procedures supporting second language reading in the brains of Chinese-English and English-Chinese bilinguals were dynamic, i.e., modulated by proficiency in the second language and perceptual features of the second language's script. Perceptual features of the scripts were manipulated through orthographic degradation by inserting spaces between the radicals of a Chinese character or between the syllables of an English word. This manipulation disrupts the visual configuration of the orthography but does not change its more fundamental design principles. We found that for English-Chinese bilinguals, higher proficiency was associated with greater accommodation, suggesting that the accommodation procedure in a bilingual individual's brain is modulated by second language proficiency. Most interestingly, we found that the assimilation/accommodation effects vanished or diminished when orthographically degraded scripts were processed by both Chinese-English and English-Chinese bilinguals, suggesting that the assimilation/accommodation procedures in a bilingual individual's brain are modulated by perceptual features of orthography. This work therefore offers a new, dynamic perspective for our understanding of the assimilation/accommodation framework for second language acquisition.