Vocabulary can be as a key factor for success, central to a language, and paramount to a
language learner. In such situation, the lexicon may be the most important component for
learners (Grass & Selinker, 1994), and mastering of vocabulary is an essential component of
second/foreign language teaching and learning that has been repeatedly acknowledge in
theoretical and empirical second/foreign language acquisition research. The intent of the current
study is to set out the nature of vocabulary acquisition alongside the expressing importance of
vocabulary acquisition. The importance of the present study is to explore the current studies of
vocabulary in order to find out common main gaps among such studies.