Abstract
This study investigated the influence of government-approved textbooks in Japan on learners’ modality knowledge as conveyed through modal auxiliary verbs and examined how this knowledge developed across proficiency levels. Learners’ modality knowledge was assessed using a multiple-choice test administered to 331 Japanese learners of English. Results showed that, overall, learners at higher proficiency levels were familiar with a wider range of modalities, and differences between intermediate and advanced levels were minor. All learners showed familiarity with the dynamic modality “can” and the deontic modality “must” but struggled with the epistemic modalities “can,” “could,” and “should” and the deontic modalities “may” and “might.” A comparison with textbook content revealed a moderate correlation, suggesting frequent exposure supports mastery. However, some modalities were acquired despite limited exposure. Hence, this study concluded that in addition to the level of exposure, the saliency of a modality affects learners’ modality acquisition.
https://ror.org/01r3kcg18 
