生成语法的主要研究对象是在句子生成过程中起关键作用并且决定各语言之间语序差异的功能性语类,其句法研究主要在于功能语类在各语言中的不同形式特征和移位表现。但是,在生成语法研究中,用以证明这些功能语类及其形式特征存在的唯一依据是据此得以解释的语言现象,这就给人以循环论证的感觉。本文列举心理语言学家和一语习得研究者的关于功能语类的实验结果,为功能语类的存在提供心理实证和一语习得实证,以此改变人们对于生成语法"是纯形式的循环论证"这一理解。

Generative grammar mainly studies the functional categories which are the significant features in sentence generation and which determine the differences among human languages.Its syntactic study focuses on the formal features of functional categories and their movement phenomena in various languages.However,there is a change of circularity in generative grammar:functional features ‘explain’ syntactic phenomena while at the same time these syntactic phenomena are often the only evidence for the relevant functional features,given that the latter can be entirely abstract.The purpose of this paper is to provide evidence for support of the existence of functional categories.The evidence comes mainly from psycholinguistic study and first language acquisition study.