I think I'm one of very few engineers who have one. Mine was put there by my boss when he ordered my badges, he noted that I had a language A-level on my CV when I started. To be fair, I used to be pretty much fluent (a few more technical words would catch me out), but six years of not using it at all has seen me loose much of it.

Whenever I'm in the terminal and I'm actually wearing one, I seem to get foreign speakers popping up out of nowhere and asking me questions. Quite surprising given how small the badges are. A simple 'where is the gate for xxx?' is fine but anything more complicated and I'm having to ask for two or three goes to get it right, a bit embarrassing. I'm tempted to order new badges to remove the issue.