In this paper, we extract grammatical items using N-grams and show that grammatical items or functional expressions can be taught efficiently by extracting expressions using the word N-grams from the corpus. First, we review the literature on corpus and grammar research from the viewpoint of Japanese language education. Then, we examine the collocation expression list of Lee & Sasaki (2015) and construct a functional expression list. For the purpose of verifying the validity of these extracted functional expressions, we have compared them with the frequency data of YNU corpus. The result indicates that the numbers of intermediate-level functional expressions tend to increase as learning proficiency increases. we argue that analyzing quantitatively learner corpora enables us to grasp the whole picture of the learner language.
