I took classes once in British Sign Language, and in those days the sign for 'Irish' was, believe it or not, flicking an imaginary flea from your shoulder!! I was insulted to say the least (I'm half Irish)
Nowadays, BSL is more politically correct, and the sign for Irish is tapping the back of your hand with the crooked index and middle fingers of the other hand.
To return slightly to this thread, it's a shame that American Sign Language is different to BSL. We can't even use the same vocab when signing!