Most French vowels are not THAT much different from English ones. (Although as I am fond of saying, “there is NO sound in French that is exactly the same as English due to the radically different basic mouth position of the two languages”)
But there are two vowels in particular that need some extra help. These are what we call “combination vowels”--so named because they are a combination of the tongue position of one vowel, and the lip position of a different one.
In this article, we will look at one of these: the sound spelled “u” as in “tu” or “vue” or “futur”. (phonetic symbol is [y]. Most students who have trouble with this sound replace it with the sound spelled “ou” as in “vous” or “fou”. (phonetic symbol is [u]. But this incorrect sound changes the meaning of words and so it is not an acceptable substitute. Here are a few examples: j'ai bu—le bout; j'ai lu—le loup; tu—tout. “Tu vas bien” is very different from “Tout va bien.!”
The secret to pronouncing this French vowel is to take the tongue position of “i” inside the mouth. (as in 'ski”) This is “the note” to hit to get this sound right. To make an “i” the tongue is rounded very high in the front of the mouth. Remember, as I teach in my video course, Mastering French Pronunciation, in the “French mouth” the tip of the tongue is always behind the front teeth with tension in the tip. And the rounding of the tongue to make the sound “i” is right behind the upper teeth along the gum ridge. (If you look in a mirror, you can see the tongue.)
Now, the other half of this sound is rounding the lips. And here is the problem: when rounding the lips, as if to say “ou”, many students also change their tongue position as if to say “ou”, and that makes the sound come out as ou”. So instead of “tu vas bien” it comes out as “tout va bien”--an entirely different meaning. The secret, again, is to hold fast to the “i” position of the tongue, at the same time as rounding the lips.
In the Rick Steves' little book, French Phrase book and Dictionary, he presents a fun way to produce this sound: “pucker your lips and say 'i.'” But once more, the key is to keep saying ”i” no matter what!
For students who have a hard time with this vowel, I have suggested actually replacing the “u” sound by the “i” sound. Say 'j'ai bi le ji” (j'ai bu le jus); or “Ti vas bien” (Tu vas bien); j'ai vi le garçon (j'ai vu le garçon). Although this would sound strange to the French listener, it would sound closer to the desired “u” sound than replacing it with “ou” as in “jai bou le jou”. Repeat the “wrong” way over and over (j'ai bi, j'ai bi, j'ai bi etc. and then finally round the lips around that sound, and you will fall naturally onto the correct sound.
I hope this helps a bit in pronouncing this challenging sound. Send me an email to let me know how you're doing.