Abstract
The present research examines the possible effects of bilinguality on additional language proficiency and the academic achievement of Iranian EFL learners. This study is a longitudinal survey of 98 EFL learners in the English Language Department of Urmia University in Azerbaijan, Iran, during the 2002-2004 academic years. It compares 56 Turkish-Persian bilinguals with 42 Persian monolinguals in terms of their performance on the FCE language proficiency tests, i.e. listening comprehension, reading comprehension, writing proficiency, and speaking proficiency in three phases of data collection. The two groups were also compared with regard to their academic achievements based on their grades consulted in every phase of the study. The subjects, who fell within the age range of 18-24 years, were similar in terms of individual (e.g. linguistic background), social (socio-economic status), psychological (motivation orientations), and educational (previous exposure to other languages) orientations. Analysis of the data submitted to a series of independent t-tests indicated that bilinguals performed significantly better than monolinguals in all measures of language proficiency except for writing skill. Further analysis of the data revealed that bilinguals attained higher levels of academic achievement. The findings, therefore, appear to provide support for the argument that bilinguality may be a good predictor of success in learning additional languages, English in this case. The findings are discussed in relation to the Threshold Hypothesis (Cummins, 1976) that assumes a minimum threshold level of competence to be attained by a bilingual in his two languages to benefit from his bilinguality; and the Interdependence Hypothesis (Cummins, 1979) that posits positive cross-lingual transfer of cognitive/academic skills between the languages one knows. In other words, through evaluating the four basic language skills separately, the researcher provides evidence that: a) the findings are within the framework of these two fundamental hypotheses in research on bilingualism, and b) knowledge of two languages may not exert the same effect on every language skill as far as additional language learning is involved. This is more evident from the key findings related to the fourth hypothesis, i.e. a lack of significant difference between the two groups in terms of their writing proficiency; a finding which encourages new avenues of enquiry for those interested in issues related to bilingualism and additional language learning. An outstanding feature of this study is that it expands research into a rarely investigated cohort, namely, adult non-balanced bilinguals. Furthermore, it explores bilinguality and its possible effects on learning of English as a foreign language among EFL learners from a part of the world where there has been minimal empirical research. It brings evidence from a new sociolinguistic context with a different combination of languages (i.e. Turkish, Persian and English). The findings of the present investigation also bring a new perspectives on how bilinguality as an important learner variable affects additional language learning. The outcomes may make significant contributions to help the individuals of either language background (i.e. Turkish, Persian) to achieve gains in additional language learning.