Form-wise error detection in a FonF-based language education system

A language education system oriented for focus-on-form instruction should recognize which linguistic forms are focused in a particular lesson, and it should also evaluate how properly the focused forms are used in learners' utterances. This paper discusses how forms should be described in the system, how the form description helps the system recognize focused forms, and how the system evaluates learners' use of the focused forms. Preliminary evaluation of the system shows that the system correctly detects focused forms and that it successfully evaluates the use of the detected focused forms. Neither incorrect detection nor evaluation failure has been attested in its preliminary evaluation.