Here goes nothin'?
(1d100)[27]
Edit: Ick. Speak 2 extraplanar languages? I mean, given 2 tieflings and 1 Aasimar (Darkvision) it sounds like having another charge of Darkness for the group to spring on unsuspecting enemies would be way more useful than a low-charisma character being able to talk to more extraplanar things. I think I'll stick with the Darkness.