Unfortunately if they made Selkath as Playable, then they will be speaking Basic as all Playable Species must be able to speak Basic.
This sounds like an assumption as I've never seen a dev say that. It would actually be somewhat easier to use 4 or 5 already recorded Selath phrases and make the player read. Also what I've always thought they should do for non-basic speaking races is give a toggle as to whether that toons speaks basic or speaks their native language (I'd like them to reverse this for some current races, Twliek for example).
That's all assuming we ever get a non-basic race, which is a giant if right now.