Is There Mentalese?

In the paper I focus on the book of Pinker The Language Instinct: How the mind creates language in which the professor of MIT in cognitive science claims that there exists some kind of language which is different from our natural language (ex: English, French, Chinese, etc.), and we people think in it but not in English or any other natural language. That is, when we are thinking, it's not our mother tongue but Mentalese carries on. After introducing Pinker's hypothesis of Mentalese, I discuss almost all his supporting arguments, pointing out the problems in his argumentation. And recurring to the thoughts of Later Wittgenstein, I try to disconfirm Pinker's points of view in that the Mentalese Hypothesis takes the way of referential theory of meaning (also be called as denotative theory) which was exactly criticized in PHILOSOPHISCHE UNTERSUCHUNGEN by Wittgenstein, and I also try to show a possible way to discuss the relationship between language and thought, between language and the actual world. In conclusion, I appreciate Wittgenstein's way of thinking, that the actual world and language are not two independent things on two sides, our language is not the mirror of reality, but is constructed from the actual world. We look, we observe, we sense and we talk about the world with the glasses of language all along. Therefore Mentalese is an unwanted hypothesis, we not only talk but think in natural language.