Based on the surname reservation generator, and what we know (or what we think we know) of the languages thus far, I'll draw some comparisons between tribes and RL cultures. Might help some pick out lore-appropriate names as a guideline. Language evolves, and...honestly, most speak either Neran or Croçais anyway, so there is no name that wouldn't "fit". I'm no language prof or anything of the sort, so this is really a series of educated guesses. Discuss?
Brudvir - Nordic, though some of the generated surnames sound a little Celtic.
Dras - Eastern European. Apparently, the language features the letters ç, ó, and ÿ, but not letters b, c, f, or q.
Hrothi - A little hard for me to pin down. A little Germanic, a little Celtic...Næroth has many accented letters, and trying to pronounce some of the names the generator spits out, I feel like I'm talking with a mouthful of peanut butter.
Janoa - Surnames the generator produces sound broadly African, and sometimes similar to words in various Aboriginal/Native American languages. Jenu is apparently a very "staccato" language, and from what I've read, accented vowels indicate a stress, so that seems to add up to me. C, f, q, and x are not used.
Kypiq - Uses ß, but not c or x. I don't even know, man. Some of the generated names sound a little Germanic, some a bit Arabic, some sound Native American, and some sound like complete gibberish.
Neran - The Neran language is equated to English, though I really don't notice any pattern from generated surnames. Anything goes?
To'resk - Croçais doesn't use "p", and is a softer, more flowing language. I hear French in it, and some vaguely Eastern European names come out of the generator, too.
Waerd - I hear a combination of Hindi, Arabic, and Native American.