This study examined the production of two types of Japanese formulaic language, i.e., collocations and idioms, through a spoken dictation task in which native speakers and advanced second-language (L2) learners of Japanese listened to a sentence with or without a formulaic string, performed an intervening task, and spoke the sentence aloud. The accuracy of production and recall time was measured as the dependent variables. The results indicated that the native speakers’ production was nearly perfect; however, the L2 learners produced many nonnative strings for collocations and idioms, and their idiom production accuracy was poorer than that for collocation. The speakers’ recall time showed that both types of formulaic language facilitated language processing for native speakers and L2 learners. In addition, L2 learners processed collocations and idioms in the same manner; however, native speakers processed collocation faster than they did idioms. These results indicate that native speakers store formulaic strings as chunks in their mental lexicon, but learners store smaller units (i.e., words and morphemes) than chunks.