ICQ99x has the option to tell people what languages you speak. But watch out if you're one of those people who fill out forms by selecting options at random, because some people can get rather annoyed when you tell them that you don't actually speak their language when that was their main reason for contacting you.

nine9 recently asked kevingpo "Do you really speak Finnish?"

As far as I know, l33t sp34k isn't one of the options in ICQ, so I'm sol.