A short speech is often a good speech and certainly has the advantage of being much less able to be a bad speech than a long speech.

A short speech is often a good speech and certainly has the advantage of
being much less able to be a bad speech than a long speech. A long speech
is often a bad speech precisely because it was not a short speech. One
seldom need repent of having said too little, but often needs much
repentence for having said far too much in too many ways too often, all
within the same speech. If you can't strike oil in ten minutes of public
speaking, stop boring and admit you have hit a dry hole.