The Interpreter Strip can be earned in one of the following languages....
BSA does NOT specify anywhere that these are the only languages available for earning the Interpreter Strip?
While they may be the only ones the BSA Supply Division currently has available, you can still earn the Interpreter Strip award for any spoken language (other than English), American Sign Language, and Morse Code.
If you cannot find an Interpreter Strip for the language you know, you can check other sources (i.e., eBay search for "interpreter strip" -spoof) for have your own patch made... just as long as it conforms to the same standards as BSA-provided Interpreter Strips. And don't forget, make sure it's text is written in the subject language... NOT ENGLISH! (Well, except ASL or Morse Code.)