I just added a short story I wrote back around Christmas. I posted to the AFMBE webboard, and now it is on my own site.
So here is a quality I wrote up for Eden Studios Unisystem. That is the engine that runs such games a "All Flesh Must Be Eaten" and "Buffy: The Vampire Slayer - The Roleplaying Game". This is designed for the Cinematic version of the Unisystem. That's the version used in Buffy, Angel, and Army of Darkness.
Whether it is from a super-science "Universal Translator" built into your Lost in Space fan club pin, an alien fish in your ear, or an old-fashioned blessing from the man upstairs you are gifted with the ability to speak and understand any language. This is a boon when trying to order food in fancy French restaurants and when you get thrown back in time to ancient Mesopotamia. Unfortunately this ability only extends to spoken (and at the GM's discretion Telepathic) communication. It does not help at all for the written word. As for ASL, well it's up to your GM to decide.
Some particularly alien life forms may have a frame of reference that is so different that it is impossible for you to understand. This is just to bad, though if the GM does it too often a drama point or two may be appropriate.