Whether you agree with Chomsky's ideas that humans are wired to learn language or not, he is certainly central to the history of linguistics and the philosophy of language. Chomsky has contributed to cognitive science, philosophy and even politics, but one way to think of him is to think about his thoughts on "Plato's Problem”.
Plato's Problem, as Chomsky called it, goes like this "how is it that someone with no education, such as the slave boy in Plato's dialogue Meno, is able to deduce the Pythagorean Theorem by answering a series of (albeit well thought out) questions? The slave boy does not have the “experience” seemingly needed to be able to understand such concepts. How are we to explain this gap between experience and knowledge? Plato purported that humans have access to basic ideas (what he called the Forms) and that we are born with this access to such knowledge. All that has to be done is to draw out the knowledge. Hence the Latin word “educere” which means (literally) to draw or lead out. So technically speaking, education is just making clear what is already in our minds.
Chomsky saw that this same problem existed with language and children. Children seem to acquire language at a fantastic rate with very little experience and without any formal knowledge of subjects, objects and verbs. They are able to tell the difference between the utterances “Shark eats man” and “Man eats shark” without any explication. And they are able to make up their own sentences with correct word order and meaning as they talk to others and themselves. So, how is this possible?
Chomsky theorized the idea of a universal grammar (UG in the linguistic jargon). Universal grammar refers to a limited set of rules for organizing language and its related structural basis. This universal grammar is present in all humans and thus explained why so many languages were possible because they all adhered to a basic set of rules, even if they were not obvious. In other words, there is a kind of innate language that human have which allows them to learn the particular language of their experience, even though that experience does not really justify the amazing output of language. Speakers of a language seem to automatically know that certain structures are not allowed in spite of the fact that they do not experience such nonsensical utterances. For example, in English it is not allowed to say “I go school”, and yet children seem to understand this and do not say it. The mistakes they do make, such as “this dog is more bigger” are ones where they have applied a rule to an exception that has to be explicitly taught. These exceptions are arbitrary. The idea of universal grammar is able to explain how learners of a language are able to deduce these rules without experience with them. They are pre-wired to do so with deeply engrained ideas of structure, grammar and meaning.
Because of the idea of an innate grammar, Chomsky is often considered a rationalist and is compared to Plato and Descartes as far as accepting the presence of innate ideas, or at least the presence of innate structures and grammar. On Chomsky's view, there is no such thing as a blank slate that is filled in with experience. Simply watching and observing children learn language shows that they are not relying on experience to do so.
Clearly, history has shown that Chomsky's ideas are not without their critics. One criticism of UG is that it is stated in such a way that it cannot be proven false. If UG is true, then is should be able to predict what new languages would be like. Yet when new languages are discovered, the rules are made to make sense with the new language and are not shown to be independent. The problem with this criticism is that it assumes that UG is a theory that is predictive in nature. It does not seem that Chomsky ever set out to predict what a language would be like. Instead he was trying to describe the reason for the gap between experience and language.