the effect of bilingualism on learning vocabularies of english as a foreign language

The issue of bilingualism is one of the problems that the education of iran has always been dealing with, and unfortunately every year, it has led many students to the academic backwardness and its irreparable consequences. choosing a language, especially the language of instruction, is one of these issues that often requires clear and obvious pproceedings. issues in the field of identity, nationality and power are closely related to the use of special languages in the classroom. in addition, language has its own dynamics and is always subjected to the processes of continuity and change and affects the communication methods of various societies. despite the valid educational arguments in support of first language education, it is necessary to balance carefully between empowering people to use local languages in the learning process on the one hand and access to world languages for communication through education on the other hand. therefore, the purpose of this research is to pay attention to some main issues of languages and education and to compile guidelines and principles related to it. of course, the realization of this requires awareness of the necessity of clarifying the language policy in education. in this research, the relationship between foreign language learners' bilingualism and their success in learning target language vocabulary will be studied. three groups of male students in three different high schools (35 people in each group) participated in this research: group a was turkish-persian bilingual students who studied only academically in persian language in urmia. group b was arabic-persian bilingual students who studied both languages academically in ahvaz, and group c was monolingual persian students. to measure the success rate of vocabulary learning, the controlled productive ability test (cpat) is used at the levels of 2000 and 3000 words. the results show that bilingualism will have a greater positive effect on the success of third language vocabulary learning, if both languages [first and second] are officially taught, as it is implemented in the case of arab-persian bilinguals.