A study investigated language transfer in the writing of 20 Spanish-speaking learners of English as a Second Language (ESL). Research on language transfer is critically reviewed, and it is concluded that existing theory supports a reconceptualization of language transfer as a form of second language (L2) learning/communication strategy that consciously and subconsciously draws on the learners' previous linguistic knowledge of all kinds and their expectations about the target language. Data are drawn from compositions written on the first day of an intensive English course, and English translations of 16 Spanish sentences after 12 weeks in the program. Analysis revealed 12 types of anomaly stemming from language transfer, occurring in: agreement, article use, capitalization, direct translation, the plural morpheme, prepositional phrase structure, pro-drop, pronouns, tense forms, verb phrase structure, word order, and L2 transfer. Occurrence of the anomaly types changed from the initial to the second data set. Frequency of direct translation, article use, and L2 transfer increased, while pro-drop and word order transfers decreased. It is concluded that this new conceptualization of language transfer enhances the simplicity and explanatory power of theory and helps account for most of the deviant forms in interlanguage. (MSE)