This work examines the developing second language (L2) grammar of a 4-year-old girl who was a native speaker of Spanish and who acquired English as an L2. The evidence suggests that, in contrast to some recent proposals for child first-language acquisition, in the case of child L2 acquisition, nonthematic properties such as Case and INFL systems appear to be operative from the beginning. Three types of evidence are presented. One piece of evidence relates to the early emergence of the copula. A second piece of evidence concerns verbless utterances containing "for." It is proposed that there is an implicit verb in these utterances and that Case theoretic reasons force movement of the post-verbal object to a pre-verbal position. In this position, the object is assigned Case by"for," which is held to be in INFL. A third piece of evidence concerns complement clauses of "want." Although the subject has difficulties in determining that "want" is an Exceptional Case Marking verb, the data suggest that she knows and obeys the Case filter. Extensive notes are appended; contains 45 references. (Author/JP)