When I ran a club for people with learning disabilities, we had a lovely Downs Syndrome young man, whose mother and father were deaf and dumb. David did not speak, but could hear a little and had picked up the 'V' sign from somewhere, he could use it very appropriately in some cases. His Dad was very concerned about this (we had a good rapport), and told me so, I just very innocently said 'I have no idea what it means', and he looked at me incredulously, but it stopped the conversation in it's tracks. Our son, who does not speak, (makes lots of noise,)can say the word b****r perfectly (he also used to use the one finger sign, seems to have forgotten that now!)