If English is not your mother tongue, you may need to make a clearer difference between the two sounds [v] and [w].
These sounds have some similarities. Both of these sounds involve the front part of the mouth. Both sounds are voiced: the vocal cords vibrate at the same time that you say each sound.
Now, here are the differences:
[v] is a fricative.
- The lower lip lightly touches the upper teeth. The contact is not quite complete.
- When you say the [v] sound, the air leaks through the narrow opening between the lower lip and upper teeth. You should feel and hear friction as the air passes through.
[w] is a semivowel.
- The two lips protrude, forming a round opening, much as they do when you say the [u] vowel in cool. The opening is not too small.
- When you say the [w] sound, the air passes freely through this opening. You should not feel or hear any friction as air passes through the opening.
Use a mirror to practice saying these sounds. Look for the position of the lips, and listen for the presence or absence of friction. You can practice making the difference between word pairs like these:
veil-whale vein-wane vest-west vent-went