In light of the fact that L2 pronunciation errors are often caused by the transfer of well-established L1 sound systems, this paper examines some of the outstanding phonological differences between Persian and English. Comparing segmental and supra-segmental aspects of both languages, this study also discusses several problematic areas of pronunciation facing Iranian learners of English. To reach such a goal, thirty EFL learners were randomly selected from three levels of beginning, intermediate, and advanced students enrolled for the Fall term in 2008 in one of the private institutes in Shiraz. Their pronunciations of a list of 40 words and 8 sentences were analyzed through read-aloud task followed by an interview. The words have been recorded though a computer-based files adjusted for voice. The result of the data analysis indicated that our EFL learners at three levels confront considerable problems in areas that are absent in their mother tongue or converged into one item which is technically termed as coalescence. In order to compensate for the difficulties encountered by our EFL learners, we as teachers should integrate pronunciation teaching in our classroom syllabi so that they will become conscious of the differences in the sound system of the two languages. In this way, the Persian learners of English will be helped to become proficient speakers of English with rare or no residue of foreign accent in the pronunciation of target words, phrases, or sentences, thereby leading to more intelligibility of their utterances.
