This study examined the development of spoken discourse among L2 learners of Japanese who received extensive practice on grammatical chunks. Participants in this study were 22 college students enrolled in an elementary Japanese course. They received instruction on a set of grammatical chunks in class through communicative drills and the memorization of dialogues that contained the target chunks. The development of the students' spoken discourse was examined through spontaneous conversations and narrative tasks administered twice during the semester at five-week intervals. Results showed that the students produced twice as many grammatical chunks in the second data collection session, with a wider range of chunk types. The frequency and range of the chunks in the narrative task were about half of those recorded in the conversation task. The participants also showed increasing sensitivity to discourse features over time, suggesting that memorized chunks served as a basis for the creative construction of discourse. (Contains 5 tables and 3 notes.)