A Research On The Mechanism Of Language Switching On Simple Sentence Comprehension:Evidence From Mongolian-Chinese Bilinguals

Language switching has been a hotspot of researches on language comprehension and production in the field of linguistics and psycholinguistics.The majority of cognitive and neurocognitive studies examining switching between languages have focused on the processing of a series of single,unrelated items(e.g.,unrelated words,numbers)rather than switching between languages within meaningful sentences.And the cognitive and neurocognitive studies on intra-sentential code-switching are mainly based on Indo-European languages.Few studies have explored intra-sentential code-switching in Mongolian-Chinese bilinguals.Mongolian and Chinese belong to different language families and have different word orders.Chinese is an SVO language,while Mongolian is an SOV language.Given that both morphological and syntactic structure of Mongolian and Chinese are totally different,the study of intra-sentential code-switching in Mongolian-Chinese bilinguals must be explored.Is intra-sentential code-switching more effortful in Mongolian-Chinese bilinguals? What are the cognitive or neural mechanisms which drive these intra-sentential switch costs?In the present study,it is the first time to investigate the cognitive processing of intra-sentential code-switching in Mongolian-Chinese bilinguals,using self-paced reading behavioral measurements,moving window eyemovement measurements and event-related potentials measurements.In Research 1,the stimuli are comprised of 120 sentences,each of which appeared in four conditions.The four conditions include Chinese unmixed sentences(“Ba”-construction),Mongolian unmixed sentences(declarative sentences),Chinese mixed sentences and Mongolian mixed sentences.Among them,half of the sentences ended with a congruent word,and the other half with an incongruent word.Experiment1 and 2 are to explore the features of the switch costs in behavioral level.Experiment 3 is to explore the cognitive mechanisms of switch costs from earlier stages to later stages in eyemovement level.Experiment 4 is to explore the neural mechanisms of switch cost from earlier stage to later stages in electroencephalography level.In Research 2,Chinese sentences and Mongolian sentences are both declarative sentences.They do not share the same word order,because the word order of Chinese is SVO,while the order of Mongolian is SOV.The research question is to explore the effects of non-shared word order on intra-sentential code-switching.Experiment5 and 6 is to explore the features of the switch costs under non-shared word order condition in behavioral level.Experiment 7 is to explore the cognitive mechanisms of switch costs from earlier stages to later stages under non-shared word order condition in eyemovement level.Experiment 4 is to explore the neural mechanisms of switch cost from earlier stages to later stages under nonshared word order condition in electroencephalography level.The findings are as follows:(1)Because of the influence of L2 Chinese environment,the second language of Mongolian-Chinese bilinguals in university is the dominant language.Thus,they read Chinese sentences faster than Mongolian sentences.(2)Reading times showed a significant switching cost for codeswitched sentences in both code-switching directions in behavioral level,though switching costs were higher into the Chinese than into the Mongolian.Eyemovments and ERPs showed that switch costs were higher into Mongolian in earlier stages while higher into Chinese in middle and later stages.(3)Switch cost of intra-sentential code-switching originates from inside and outside the bilingual lexicon.(4)Word order influences the comprehension of intra-sentential codeswitching.Shared word order facilitates the integration of each elements of one sentence,while non-shared word order hamper the integration so that the finding show a switch cost associated with sentence level integration.