This longitudinal case study followed a Hebrew-speaking child acquiring L2-English, focusing on her production of articles. Although the child had already developed significant aspects of the Hebrew determiner system, her acquisition of English followed a typical developmental route for first language acquisition: single words; telegraphic speech; and complete sentences, including articles. The child's acquisition of definite and indefinite English articles was based on different strategies: the was dropped for a long period, but was then incorporated in full sentences; whereas a, which lacks an equivalent form in Hebrew, appeared earlier in the child's utterances, but only in memorized templates of [a + Noun]. Moreover, the proportion of cases in which English articles were omitted in obligatory contexts decreased over time, whereas additions and substitutions increased. These findings bear upon the role of functional categories in language acquisition and the endeavor to understand the extent to which children's L1-based knowledge may guide or interfere with their mastery of a second language.