These seem... kinda redundant to me; why do we have both? Which should we use primarily?
Being a site dedicated to languages, I think the idea of adding language to the end of a tag is unnecessary.
Obviously we don't need both, since questions about Klingons or Klingon culture excluding language presumably won't be on-topic here.
However, to make it clear that the tag is only about the Klingon language and not anything else to do with Klingons, I suggest using klingon-language as the primary tag name.