Language acquisition is the process happened on the people when they learn a native or a second language (L2). While, the second language acquisition (SLA) is a certain process when the people learn a second language; language(s) learned after the first language. Stephen Krashen (2009) as one of the experts of language acquisition explained that people acquire language by comprehending what they hear and read. The result of language acquisition may consist of ability on language production like speaking or writing skill. One of SLA aims is to investigate how the people use their linguistic system during they comprehend or produce the speech.
So, the people who learn the other languages as L2 should consider some factors in order they seize their goal in learning SLA successfully.