why does vietnamese sound bad (kinda)?

im NOT trying to offend but it sounds bad while other languages are decent and japanese and korean in my opinion sound the best....im cambodian (little chinese) and speak my langauge and sounds decent...anyways i wouldnt say Vietnamese is horrible its speaking but Writing is Perfect know one can beat them at writing

my gf use to tell me she doesnt speak her native philipino langauge, but the other day i heard her speaking it with her mom. same with some friends at work, they say dont speak vietnamese/urdu, but i catch them speaking it. why?