He can talk but is delayed and isn't conversational so can't tell me where its come from.
This morning when getting ready I pointed to a character on his t-shirt and said "what's this" to which he replied very matter of fact "fuck off"
We soon realised that he's associating the pointing to the swearing, so we think somebody has been showing him the middle finger and teaching him that it means "fuck off" and he's now interpreting all pointing as that.
He doesn't know what it means, he's not being naughty or rude. Somebody has taught him it and it's going to take forever to change the correlation in his mind.