The Lao (and Thai) word for ‘cat’ is not “meow” but maaw. This sounds onomatopoeic to us, but that doesn’t prove anything about its origin. The Vietnamese is con mèo; I don’t know if the second syllable is a loan from Tai (which includes both Thai and Lao) or was borrowed into Tai or whether one or both were borrowed from Chinese mao, but if the latter is the case, you’d have to investigate the Ancient Chinese form, which might be quite different. Etymology ain’t easy.
Fair point. If it is a Chinese loanword then that would have to be investigated though the Lao etc might have later leapt on it imagining it corresponded to the sound they heard. And maaw sounds very close phonetically to what we hear. This is pure speculation but a list of the representation of cat meows in all languages would be interesting. I am guessing all would start with “m” or “n” followed by a diphthong or maybe just an aaw diphthong. Mind you, dog bark sounds vary markedly from language to language so I could be talking through my hat again.
I did read your original post, which did not specify non-avian exclusivity (although it does now, since your recent edit), and I did note that the OED entry on meow is “not really about animal names, but still interesting”.
Sorry, etymol, you were right. I have found I word my original posts pretty badly and get taken to task by many later posters so I hurriedly and inaccurately edited it.
Thanks to everyone for the interesting responses.