This contrastive study examines the role of grammaticized aspectual categories in processes of language production for Japanese native speakers and advanced-level German learners of Japanese. I first demonstrate on the theoretical level that the aspectual forms of Japanese verbs (the simple form and the tei -form) relate to complementary notions: the EVENT-perspective (with at least one BOUNDARY) and the STATE-perspective (without any BOUNDARIES). Then, I investigate influences of a verbal prompt which indicate a certain aspectual perspective on perception and conceptualization for both speaker groups, using film clips showing ongoing motion events as stimuli. The results are as follows: The L1 Japanese speakers establish a referential frame that requires a language-specific perspective (namely the STATEperspective) with respect to their knowledge of the complementary aspectual categories. Their decision for information organisation is then reasonably independent of any external prompt. In clear contrast, the L2 Japanese speakers typically adopt the aspectual form used in the verbal prompt. On the other levels of speech production, however, they follow the L1-related principles of information organisation. The categories grammaticized in L2 hardly influence conceptual planning in L2 production. These empirical results support the thinking for speaking -hypothesis.
