This study clarified self-regulated learning processes in EFL in order to propose a more adaptive learning system. We developed an English vocabulary learning system for Japanese. It presented each word in an example sentence and the Japanese translation of the sentence except for the target word upon user request. We sought to examine how learners use this system as a scaffold. Five college students of lower and intermediate ability used the system for six weeks and took exams. We found that the intermediate-ability group learned more vocabulary than the lower-ability group, even when compared to similar-level students using another system that provided only words and translation. Process analyses revealed that the lower-ability group depended on help all through the period, while the intermediate-ability group decreased its use gradually as if to check their learnability. This suggests that the future system have both scaffolding and fading-out functions adaptable to learning states.