Empty vessels make the most sound
You will always find that a person with very little learning loves to jabber all the while and laugh and joke and make a lot of unnecessary noise. This is because the person doesn't really have any substantial matter in their head and so hides this fact with a lot of meaningless chatter. But the person of real substance looks around, observes and when he or she speaks, it is to say something really meaningful. That is what is meant by this proverb.
Hence when we are in a conversation we should only take a fair share of the conversation and not keep prattling on as if no one else is there. This will show that we respect other people's opinions and wish to hear them out too. It would also send out the message that we are not superficial people who only bore others with our pompous talk.
