&gt; Parse trees are cool to look at, but what can I do with them?<p>One really simple and obvious thing is word sense disambiguation.  Plenty of homonyms are different parts of speech (e.g. the verb &quot;lead&quot; and the noun &quot;lead&quot;).  I&#x27;m sure there&#x27;s lots of more sophisticated stuff you can do as well, but this might be the lowest-hanging fruit.