Abstract:   Inhibitory control, language proficiency, related issues of tasks and working memory are the main factors influencing language switching costs. As to the question “which factor plays a predominate role in mediating the bilingual’s language switching cost, inhibitory control or language proficiency?”, there is a heated debate between Inhibitory Control Model and Language-Specific Selection Model. Therefore, the related studies in the future should further explore whether the age of second language acquisition and language use influence the bilinguals’ inhibitory control, whether language switching cost and task switching cost are similar in nature and the relationship between language switching cost and working memory.

Key words: language switching costs, inhibitory control, language proficiency, task factor, working memory