hahaha, sadly no it’s not, that’s a kind of urban myth tbh, I’ve never known anyone who used it except as a joke. the welsh for microwave is actually “meicrodon”, which I always liked because it sounds like a teeny tiny mafia boss
honestly a lot of things in our language are hilarious to the point of not sounding real at all, like “wnco mwnco” which means “him over there” and has the added advantage of making it sound like you’re doing a monkey impression as you point at the person you’re indicating (use with caution)
the welsh for ladybird (ladybug, whichever) is “buwch goch gota” which means “little red cow”
“ironing board” in welsh is “bord smwddio” pronounced as ‘board smoothio’ and makes you sound like a drunk casting a spell from harry potter
instead of “over the top” we have “dros ben llestri” which actually means “over the crockery”. my nan used to say ‘tickery tockery over the crockery’ and that was when you knew she’d really had enough
"good god” is, I shit you not, “jiw jiw”
you can describe a place as being “mor ddu a bol buwch”, meaning “as dark as a cow’s stomach”
instead of “don’t cry over spilled milk” we have “paid codi pais ar ol piso” which actually means “don’t lift your petticoat after pissing”
one of my all time favourites: “Mae hi’n bwrw hen wragedd a ffyn”, meaning “it’s raining old ladies and sticks” (there might’ve been a shortage of cats and dogs idk)
and there’s a ton of smaller stuff, like “taxi” becomes “taccsi” because there’s no x in our alphabet. there’s also no k, v or z, so “kilogram” becomes “cilogram” and “volt” becomes “folt”, and you’re only allowed j for english words we snatched up (Japan becomes Siapan for technical linguistic reasons I’m not clever enough to explain)
also “noodles” are “nwdls” (sometimes I think we just do things to fuck with the English)
I could go on and on