&gt; <i>the process that converts &quot;the man who has written the book will be followed&quot; to &quot;will the man who has written the book be followed?&quot; instead of the incorrect &quot;has the man who written the book will be followed?&quot;</i><p>And yet the following is also correct - in terms of real-world usage, not some prescriptive definitions:<p>&quot;The man who has written the book will be followed, right mate?&quot;<p>&gt; <i>you will find that the rules must involve imposing some sort of tree structure on the original sentence.</i><p>The rules are, and the brain may be, but I feel those are different tree structures. Moreover, I wonder if the &quot;tree structures&quot; of our brains aren&#x27;t just artifacts of recursive pattern matching - we also know that when reading, humans process whole groups of words at a time, and only if there&#x27;s some mismatch they process pieces in more detail. Any recursive process like this will generate a tree structure as its side effect.<p>Anyway, thanks for the examples. I might pick a linguistic book at some point. Right now the idea of understanding natural language by parsing it into &quot;NOUN PHRASES&quot; and &quot;VERB PHRASES&quot; and stuff seems completely backwards, given how humans have no trouble parsing &quot;invalid&quot; sentences, or using them - especially in spoken language.<p>(Not to mention our ability to evolve the language, and how the grammatically invalid constructs tend to be introduced, used, understood with no trouble and at some point they become grammatically accepted - see e.g. recent acceptance of &quot;because &lt;noun&gt;&quot;).