The present paper proposes and evaluates a readability assessment method designed for Japanese learners of EFL (English as a foreign language). The proposed readability assessment method is constructed by a regression algorithm using a new set of linguistic features that were employed separately in previous studies. The results showed that the proposed readability assessment method, which used all the linguistic features employed in previous studies, yielded a lower error of assessment than readability assessment methods using only some of these linguistic features. (Contains 4 figures and 2 tables.) (more…)