Vocabulary knowledge plays an important role in language learning. Language ability of
learners will be improved overall by vocabulary improvement (Linse, 2006). The vocabulary
is more important than grammar as the basic of language (Ghadessy, 1998; cited in
Sripramong 2004). The more vocabulary one knows or acquires, the better more sentences
they could create; otherwise, language learning won’t occur. So it is known that “word” is
the most common element in sentences because a language is a collection of words. The
complex materials need to be understood through the vocabulary knowledge as an important.
Sufficient English words can make learners efficiently communicate and fundamentally
comprehend on English articles and academic essays (Dickinson, 1987; cited in Sripramong
2004).