"Love is silent." It is really interesting for me, too.
I think it is sometimes true, but sometimes you cannot say so. In my opinion, you are happy when you are just sharing your time with your boy/girlfriend. There is no words, but you feel comfortable just being with him/her. However, I think we also need the time to share each other's opinions or thoughts. We cannot understand all of others' thoughts without words. We sometimes tell or listen to others for trust or to build deep relationships.
