The ability to use language may be one of the most important features that makes human beings as human, so language acquisition draws much attention from linguists, psychologists, and language learners from long time ago. The process of first lan-guage acquisition has little to tell us about how a second language is acquired. FLA can tell us something about SLA since they are both the language acquisition process of human beings and share some similarities like needing input stimuli, similar developmen-tal sequence etc.