Why do we find it important to communicate our beliefs?

People love to talk about what they believe. However, one can never know for sure that someone actually believes what they say they believe. We can’t get into someone else’s head. Yet, it seems to me, people pay far more attention to what people say than to what they do.

The idea that “actions speak louder than words” is kind of moot if everyone is blind. If you’re deaf, then actions are all you have to go on. Who is better off? The blind guy or the deaf guy? Why?