【正确答案】正确答案：Language acquisition is one of the central topics in psycholinguistics. Acquiring a first language is something every child does successfully, in a manner of a few years and without the need for formal lessons. Four phases are identified and acknowledged in the process of language acquisition: holophrastic stage, two-word stage, three-word utterances, and fluent grammatical conversation stage.

【答案解析】解析：(考查语言习得的定义)