Eighty-one seventh- and eighth-grade students (age 12-14) learning English in Japanese classrooms were tested on their knowledge of English case-marked pronouns in sentences like "He likes her," *"He likes she" and *"Him likes her." The aim of the study was to evaluate the predictions of three theories of second language (L2) development against the results obtained. Given the case-marking properties of Japanese, the Full Transfer/Full Access model of Schwartz (1998) and Schwartz and Sprouse (1994; 1996; 2000), the Minimal Trees model of Vainikka and Young-Scholten (1994; 1996a; 1996b; 1998) and the Lexical Learning/Lexical Transfer model of Wakabayashi (1997; 2002) make different predictions about the kinds of patterns of case-marked pronouns that will be found in the second language English of early learners with Japanese first language (L1). It is argued that the results are consistent with the predictions of the Lexical Learning/Lexical Transfer model, but with neither Full Transfer/Full Access nor Minimal Trees. (Contains 8 figures, 6 tables and 20 footnotes.)