Timber rarely uses language when I am in his line of sight. When I am upstairs, he chatters away which sounds like much the same situation you have with Dorian. When I am out of sight, like in the bathroom or in another room where he can't see me, he will vocalize. While we are together, he whistles and makes his other range of sounds, but he saves language for trying to get me to come to him it seems. When several of us are in the room with him, he will sometimes use language also, but it seems to be an attention getting thing. Like if we are talking to each other and not to him, he will try to get in the conversation and draw attention to himself. Wish I could read his mind!