汉语作为第二语言学习的脑机制

Brain mechanism underlying learning Chinese as a second language

国家兴,语言强。近年来,汉语作为第二语言学习的认知神经机制研究日渐增长,但汉语二语学习脑机制的系统归纳及相关理论模型仍处于起步阶段。基于汉语二语学习近20年的脑机制研究,以及最新二语学习脑机制的研究和理论,可以归纳主要发现为:1)汉语声调学习最初依赖右颞上回和右额下回,掌握后转而依赖左颞上回;2)汉字字形学习与双侧额下回及右梭状回有关,而汉字语音学习则与左颞顶叶区相关;3)汉语二语学习初期会依赖右脑重要脑区(额下回、梭状回等),随汉语能力的提升,这种依赖减弱。综上,汉语二语学习与右脑关系密切,经历了由右侧功能主导转向双侧化或者左侧化的动态大脑发展变化过程。汉语学习者所采取的二语学习方法及其语音听辨能力,会影响学习者的语言功能、脑结构及其脑功能网络连接方式。未来研究可以从被试语言背景、研究范式和内容、数据分析等角度出发,探寻汉语二语学习的有效方法,构建并完善汉语二语学习认知神经机制的相关理论模型。

With the fast growth of the Chinese economy,the Chinese language has become one of the most widely spoken world languages.There is a steady growth of empirical studies on the neural mechanisms underlying the learning of Chinese as a second language(L2).Yet,research on the specific brain mechanisms and the corresponding theoretical models for Chinese L2 learning are still in their infancy.Research in the past two decades has revealed that:1)Chinese tone learning relies on the brain areas of the right superior temporal gyrus and the inferior frontal gyrus when learners are at a lower L2 proficiency,and then shifts to the left superior temporal gyrus as they reach advanced proficiency;2)Chinese character learning is related to bilateral inferior frontal gyri and the right fusiform gyrus,whereas Chinese phonological learning is closely related to the left temporal-parietal areas;3)Overall,Chinese L2 learning relies more on right-hemisphere brain regions(e.g.,inferior frontal gyrus,fusiform gyrus)at the early stages of L2 learning,and the reliance decreases with the improvement of L2 competence.To sum up,Chinese L2 learning undergoes a dynamic neural change from an early stage of right-hemisphere reliance to a later stage of bilateralization or left-lateralization.L2 learning strategies and learners’auditory perception abilities are found to influence brain functions,neural structures,and connectivity networks.Future research on Chinese L2 learning can investigate learners of varying characteristics,triangulate research paradigms,and synthesize behavioural,functional and structural brain imaging data altogether to find efficient Chinese L2 learning strategies.More future research in this field will advance the current theoretical models and understanding of neuroplasticity in Chinese L2 learning.