Speech teach people who have knowledge of listeners hear little but do not care to hear or listen to, but they could not understand. Make it possible for a malicious user to teach the knowledge, waste of time.
To speak to those who have little knowledge listened. But the audience did not care to listen. Or listen to, but could not understand. The people who teach that knowledge is a waste of time.
Speaking to teach people with little knowledge to hear. But the audience didn't bother to listen. Or listen to, but was unable to understand. Make those who taught the knowledge that a waste of time.