C.M.
I think babbling is a good sign. Sometimes kids won't actually talk because whatever means of communication (i.e. sign language, babbling, pointing, looking etc.) is working. They have no need to change the method they are using. Sometimes you can nudge them into the next stage by not fulfilling their request when they ask that way, but rather, when they signal for it, say it in their words. For instance, if they are asking for a cup and point to it, you would say "cup" and wait until they say something that is resembling "cup" (repeat several times) then give it to them.