Claiming to be able to speak languages he doesn't is another of Andy's favourite lies. I've seen him claim he speaks six languages (link below) on tumblr. He's claimed to have learned Irish from this grandfather, and that he speaks French, but (IRCC) it's "18th century literary French" or something of that nature. Which is why he needs an actual French speaker to help him translate things.

http://andythanfiction.tumblr.com/post/44496687605/how-many-languages-do-you-know