It&#x27;s precisely how strongly we conform to grammar, without having been taught it, which shows that it&#x27;s key to our internal representations&#x2F;to how we learn language.<p>Here is the undeniable proof that syntactic structure exists. Consider the sentence `The magician pointed at the man with the hat.&#x27;  This is a perfectly natural sentence, of which there are two likely interpretations. One is that the magician used a hat to point at the man. The other is that the man who was pointed at wore a hat.<p>What distinguishes these sentences? Only the underlying syntactic structure, of whether to parse it as `the magician pointed at (the man) with the hat&#x27; or as `the magician pointed at (the man with the hat)&#x27;. This `hierarchical structure&#x27; of our sentences is syntactic structure at its essence.<p>You argue that humans can understand sentences with whatever grammar, and parsing is pretty much pattern-matching of words. But what about the sentence pair : `Benny chased Jenny&#x27; versus `Jenny chased Benny&#x27;? These have the same words, and mean different things. It is only our syntactic understanding of how words are ordered in English that allows us to understand these sentences.