Abstract
Since 2016, this author has been studying how grammatical knowledge can be applied in classroom situations in a Japanese teacher training program. This paper reports on exercises to explain grammatical errors in ways effective for hypothetical adult and youth learners. Over the course of multiple practice and review sessions, explanations offered to hypothetical adult learners became more concise, although the explanations tended to be drawn directly from the teacher class learning. In the case of hypothetical young learners, students learned to employ simple explanations free of difficult grammatical terms, though the selection of examples and sentence structures displayed the need for further improvement.
