I have a lot of students from slavic speaking countries and a common problem they face is, like Chekov above, the pronunciation of the V sound. Too often I hear and see their mouth make the W sound instead. Different native languages present different pronunciation challenges but this one I think is not so terrible. This is because most Slavic students can easily produce the F sound and guess what, we use the EXACT same part of the mouth as with V. Thus "Face and Vase". If you can say one, you can say the other.
The ONLY difference is that V is voiced. This means we engage our vocal cords with the V while the voiceless F does not use them.
So, the challenge of the V sound is not so much retraining mouth muscles as in some foreign sounds but simply remembering, if it is a V, press your bottom lip to your upper teeth just as you do for F, engage the vocal cords and voila! (that's French!), you're speaking like a native.
I'm not an expert in pronunciation but there are some who are and do a great job explaining such things. I recommend this site for a more detailed explanation. Be sure to watch Rachel's video explanation a little bit down as well. She does a great job and I recommend all my student subscribe to her channel.
