At Mandela's funeral, the sign language interpreter was reportedly a fake... I mean, he may have been the official signer for all I know, but he wasn't really signing in any language that anyone can figure out so far.
'The South African government is investigating “alleged incorrect use of sign language” after a man stood on stage and pretended to translate speeches by President Obama and several other world leaders at Tuesday’s service in Johannesburg.'
He gave the appearance of full communication,
but it was all just empty gesticulation.