A Language-research experiment designed to examine the linguistic competence of bilingual Italian-American children demonstrates that structures shared by Italian and English are acquired in approximately the same order and at the same rate, and that the sequencing of specific structures reflects linguistic complexity. Structures appearing in both languages are believed to have a common underlying base and realized by the same set of transformational rules. The definite sequencing evident in child-language acquisition may have implications for second-language acquisition by adults; instructional materials and programs could be established with this in mind. (VM)