Communication is to relationships what sunshine is to flowers. A regular dose is the lifeline that gently helps with continuous growth. There's non verbal communication: that knowing glance, a long warm hug, a gentle touch, etc.These can be very effective in an environment where words can't be spoken or when you both just want to enjoy the silence.
Then there are our words; remember its not what you say but how you say it that makes a huge difference. If you want to maintain or even start a relationship I implore you to say something. May not come out right, but if you matter to that individual they'd accept your fumbled effort over your silent distance.
An important aspect of communication is knowing how to listen (sometimes it seems I have lost a little of that gift)