[LexBaird]

I suggest DNA testing of words around the world to determine where the missing Welsh vowels went.

There's only one vowel in "DNA". Besides, the Welsh seem to make do with the "sometimes y and w" clause.

[IronJack]

There's only one vowel in "DNA".

True, but it's just an abbreviation. "Deoxyribonucleic acid" has some to spare!