A study investigated the interaction of cognitive, cultural, and linguistic factors in second-language concept formation in adults. Specifically, it examined how seven college students in a lower-division intensive Spanish class developed new gender concepts when learning a second language. Course instruction focused on concept construction at linguistic, cultural, and abstract levels. In recorded individual interviews with the instructor, the students performed two problem-solving tasks: (1) defining three nouns denoting specific gender cases for animates in Spanish; and (2) writing three complete sentences to accomplish a specific task in a restaurant. Immediately after completing each task, the students were asked to explain why a particular linguistic form they used in written work was correct or incorrect, focusing on gender markers. The text of one interview is presented here. Analysis of the interviews suggests that there is an interaction between cognitive, cultural, and linguistic factors affecting concept construction in second language learning situations, but also idiosyncratic, individual learning approaches and strategies and incorporate elements from the learner's own cultural history. Less advanced learners showed only implicit intralinguistic knowledge, with no understanding of the relationship between intralinguistic and extralinguistic-cultural knowledge. (MSE)