> But what is **akwa?? How is it attested as the IE word for "water" other
> than in a couple of western IE branches?
There are suggestive forms elsewhere, eg:
Hitttite e-ku-uz-zi "drinks" 3 pl a-ku-wa-an-zi
Greek: koadama someone who lives by the water
There is also a suggestion that Thalassa in Greek in not a loan word, but is
made up of *dhl + akw-ya
In any case, Latin + Germanic + ? Celtic is reasonably convincing.
Peter