I would pronounce these words like this: - Clywed (clw-wad) Rhywbeth (rwbath) Bwyta (byta) (with “y” pronounced as the “u” in the English world “much” Wyt (oot - English phonetics)(ŵt - Welsh phonetics) Wyth (listen to this https://translate.google.co.uk/#cy/en/wyth, it's better than what I can explain despite sounding horribly robotic) Llwybr (listen to this https://translate.google.co.uk/#cy/en/llwybyr I have adapted the spelling of the word to make Google Translate pronounce it correctly) Cwymp (either cwmpo with a short “w” or cwympo with the “wy” pronounced as “wi” in the English word “with” Gwrth-wyn-ebu (Gwrth with short “w”, wyn as the English word “win” ebu as “ebby” in the English name “Debby”. Depending on which dialect you are learning, “u” is pronounced like the Welsh “i” in the South of Wales, and like the “i” in English “it” in the North. For “teithio” both vowels need to be pronounced individually. Like this: https://translate.google.co.uk/#cy/en/teithio In natural Welsh “ein” is pronounced like like the “un” in English “untangle”. This word is an exception, as the spelling was chosen resemble Latin. Usually in Welsh words, “ei” should be pronounced as in “teithio”. “W” does sound like “oo” but it could be long or short in length without changing the actual sound. “Bwthyn” in English phonetics should be spelled “boothin”, but the “oo” needs to short, similar to the “u” in “put”, although, I am hesitant to say this because American English tends to put some “u” sound (as in “buck”) into the “oo”, which shouldn't be in what I am trying to explain. Maybe it would be better to say that it's the same as “w” in “was”; it is usually a vowel in Welsh, but don't worry about this; it's the same sound.

In my dialect (north-west Wales) I pronounce them as "w". So phonetically, I would pronounce clywed as “clwad” or “clw-wad” and rhywbeth as “rwbath”.