This paper analyzed two returnee’s vocabulary using materials. In particular, this paper analyzed the verb error focused on ‘Why did these mistakes occur?’ Two bilingual returnee lived in the Czech Republic for 2.2 years. They went British International School in there. The causes of verb error has been presented largely in four. One is the interference of the English representation. They often used the Korean verb directly translated English verb instead of a suitable korean verb. The second stems from ignorance of the collocation. It was a mistake in not knowing the variety of collocation occurring expression. The third was due to lack of thinking skills. The ability to discriminate the thesaurus meanings and the ability to categorize the meaning must be educated. if there is no syntactic pragmatic knowledge, it is difficult to speak right words. The fourth was related to the lack of background knowledge. If you do not use the proper verb it is due to ignorance about the culture.