The role of language transfer in the acquisition of English as a second language as indicated in the production of relative clauses was examined. Analysis of adult Arab students' written responses to a variety of test types revealed that (1) language transfer is a significant factor in second language acquisition; (2) there is a distinction between inferencing transfer and non-inferencing transfer; and (3) in addition to strategies already known in the field such as transfer, simplification, and overgeneralization, the Arab students employ various perceptual and production strategies. The responses of these learners indicate that both interlingual and intralingual errors are found in their interlanguage. As a result, an adequate account of the process of second language acquisition has to include a multifactor approach in which the first and second languages, transfer, other production and perceptual strategies, and language universals play complementary roles. (Author/MSE)