The aim of this book is to investigate the effectiveness of an Intelligent Computer Assistant Language Learning (ICALL) program on Turkish learners' vocabulary learning. Within the scope of this research, an ICALL application was developed and used in an English language preparatory class to measure its effects on students' achievement in vocabulary acquisition as well as their attitudes towards such an ICALL environment. It is believed that this study can provide language teachers with necessary knowledge and enthusiasm to incorporate an ICALL application intended to teach vocabulary in their language classrooms. It can also be concluded that the morphological analyser of YVZ has proven to be technologically mature and pedagogically effective.