You do subconciously. When you read &quot;Dave punched John&quot; you don&#x27;t need to think &quot;hmmm, is &#x27;John&#x27; the object or the subject?&quot; but if your brain hasn&#x27;t figured out which is the object and which the subject you won&#x27;t know who is hitting who.<p>You don&#x27;t need to be able to name or define parts of speech but you need to be able to parse them, or you won&#x27;t understand anything.