Thanks for your answers. You&#x27;ve raised a lot of good points, and I need to think them through.<p>&gt; <i>the claim is that when you see an invalid (cannot be parsed into a proper tree) sentence, you have a gut feeling that it &quot;sounds off&quot;, and if you&#x27;re a native speaker you would never accidentally produce such ill-formed sentences. You can still understand the meaning of a sentence like &quot;I this morning fish eat&quot; but you also immediately notice that it&#x27;s &quot;off&quot; - and that&#x27;s the phenomena that syntax tries to explain.</i><p>I see. Yeah, most of the way I think about how mind processes language comes from focusing on that &quot;gut feeling&quot;, that on one hand tells you that this perfectly understandable sentence is somehow &quot;off&quot;, and on the other hand lets you form perfect sentences without ever explicitly thinking about grammar.<p>&gt; <i>First, modern linguistics is very far from prescriptive. In fact the first thing they teach you (at around the same time they make the claim that &quot;humans parse sentences into tree structure&quot;) is that linguistics is a descriptive field</i><p>It seems to me that I&#x27;ve been operating under invalid assumption that linguistics is mostly prescriptive. Thanks for that. Any recommendation for an intro book I could grab to read in my spare time?