So, if you want to estimate how many grammatical sentences under twenty words in English, the answer is, "A lot."

如果你想估计一下,用二十个英文单词,可以组成多少个符合语法的句子,答案会是,"很多"

耶鲁公开课 - 心理学导论课程节选

But they don't typically give feedback based on the syntax or grammaticality of what they say.

但他们通常不会根据儿童所说话语的语法,或者是否符合语法,来给予反馈

耶鲁公开课 - 心理学导论课程节选