Hmm, sounds like it could be a word that represents a sound.
As in Doh, Fah, etc used to practise musical scales, which are all valid Scrabble words (I lurve Scrabble!).
If it isn't in the OED, or one of the other big ones, e.g Merriam-Webster, then I would start to doubt its legitimacy as a recongized word.
Is anyone here at university? When I was at uni, I know we had access to the Oxford English Dictionary online. Perhaps someone can try to look it up. The word's not in my COD.
I've seen some dubious words used in wordgames, but none as dubious as Euouae!
For a start, aside from some made up imitative words (Anyone read Commando comics, where all the Japanese soldiers say "Aiiieee!" when they attack?), dipthongs of more than 3 letters do not exist in English AFAIK.
As to the Latin connection, I don't recall *ever* encountering it in the ten years I studied Latin. However, in Latin, u can be used as a consonant sound (pronounced like w in English), so it *may* be 'ew-ow-ae'
BUT if the u is meant to be a vowel u, there are only meant to be 5 dipthongs in Latin - ae,au,oe,eu,ui, and certainly no three letter dipthongs.
Puzzling....