All ropes speak a language if you look and listen. Movement on rock is different than rope being pulled up to clip. Watch carefully when the leader is in view, how the rope moves when both leading and placing pro. When the leader is out of view (and earshot) the rope will still tell you whats happening without a word. Its always un-nerving for me to climb with a partner who doesn't understand this.
3)on rock-climbs, the question that usually arises, is whether or not to take the leader off belay. whether or not to begin climbing is easily resolved - if the leader has used up all the rope and is still pulling, you have to start climbing. either your partner has you on belay, or he/she needs to move further to reach a stance, but in either case, you have to start climbing! when I cannot communicate with my leader, I simply keep the belay on until all the rope is gone, at which point, I dismantle the belay and commence climbing, moving no faster than the rope (thus allowing no slack to multiply).
I cut and pasted this from the last post because it was so succinct. If the rope comes tight you are on belay or the leader may desperately need you to simul climb to get to a good stance. The leader, if at a belay stance, knowing that you will climb when the rope comes tight, should put you on belay before pulling up the rope. Because it is a top rope, I do this with a waist belay for speed and switch on the fly to a belay device if warranted.
Double ropes have a greater vocabulary. If both ropes come tight, the overwhelming message is that you must be on belay. If you are not on, it is because the leader desperately needs some slack. Untie from the belay and give it to them.