Hilarious and very very difficult to understanding voice
Yes, cannot hear the word "um" at all.
Verdade. Eu sou do Brasil e Não escutei.
Is it "homem" or "homen"?
singular: homeM / plural: homeNS
I put the instead of a. Would any Portuguese person mishear it as that?
Yes, it is hard to tell them apart! O = /oo/, UM = /oom/. So, they are very similar and hard to differenciate. But over time you get it! =)
I imagine it's easier with a real person talking? Or maybe not!
But the context makes it easier :-)
They are quite different in pronunciation, the "o" is more time consuming, vibrant and open and turn the "A" is faster and inside. Put it in translate google and listen to realize the difference ;)
I noticed that you have the sound "o" in the article "o" when said alone, but the sound "oo" when it's said in "o homen".
Yes, the definite article "o" does sound as "oo" in practice. The name of the letter is pronounced just "o", though --- or, more commonly, "ó", with an open sound.
Does "comem" exsist?
Yes, for the 3rd plural person: eles comem (they eat)