It’s easier to notice if you exaggerate it. A word starting with V always has the bottom lip touching the top teeth. A word with W has the bottom lip pushed as far forward as possible and never touches teeth.
Just pushing the bottom lip around you can hear the difference from Wine <-> Vine
I honestly can’t tell the difference from the sound alone
Might be clearer in person, but they’re very distinct to an English speaker’s ear.
‘V’ is closer to ‘F’, while ‘W’ is closer to ‘U’.
It’s easier to notice if you exaggerate it. A word starting with V always has the bottom lip touching the top teeth. A word with W has the bottom lip pushed as far forward as possible and never touches teeth.
Just pushing the bottom lip around you can hear the difference from Wine <-> Vine