A study investigated the organization and development of second language lexicons among Hong Kong learners of English as a Second Language (ESL). Specifically, it compared the associations promoted by a single list of 20 frequent, common words in the learners' native language (L1, Chinese) and second language (L2, English). Subjects were 22 teacher trainees with mid-level English proficiency. They heard the list of English words and then in Chinese, and were asked to write the first word that entered their minds. The responses were analyzed for the frequencies of different response words, and the results compared to determine which similar semantic prompts inspired different responses in the two languages, and which inspired different responses. Results suggest that the L1 and L2 lexicons of this group are very different in structure. The L1 and L2 prompt words evoked neither similar frequencies of responses nor similar semantic associations in the two lexicons, and individual word responses did not elicit similar frequencies of word types in L1 and L2. It is concluded that different languages produce different storage and retrieval systems, refuting the notion of a common underlying principle of bilingual proficiency. Contains 16 references. (MSE)