Abstract
The present study focuses on discourse markers (DMs) in its consideration of the issue of authentic texts as a primary input source for learners. DMs are considered to be characteristic items in natural speech, whose use can be indicative of authenticity. In order to judge the authenticity of texts, the study investigates the presentation of DMs in EFL textbooks for Japanese college students and adult learners, and compares it with the distribution of DMs in spoken corpora. The frequency analysis of DMs in nine EFL textbooks revealed that there were significant differences between the dialogue in the textbooks and the speech data of native speakers. Although this finding replicates those of previous studies, quantitative and qualitative analyses on the textbook dialogue and the speech data of Japanese EFL learners suggest that the proficiency level of target users is a key factor in considering what kind of and how many DMs should be incorporated into textbooks. From the perspective of language acquisition, it would be preferable to carefully select frequent and easy-to-use items, and to design textbooks according to learners' proficiency. In other words, there are several important questions regarding authentic texts as the one and only model for textbook language.
