The French language can be distinguished from many other languages by its nasal vowels. Languages such as English also have nasal vowels but they are followed by nasal consonants. French, however, has fully nasalized vowels which are not followed by nasals.
French has four nasal vowels. They are the low mid front unrounded, low mid front rounded, low mid back rounded and low back rounded nasal vowels. In a number of dialects, the low mid front rounded nasal vowel has disappeared in favour of the low mid front unrounded nasal. This is not surprising because the low mid front rounded vowel is far more marked than the unrounded one.
The low mid front unrounded nasal vowel occurs in a number of words. These include vin (wine), singe (monkey) and faim (hunger).
The low mid front rounded nasal vowel is less common than the low mid front unrounded. It occurs in words such as parfum (perfume), un (one) and lundi (Monday).
The low mid back rounded nasal vowel occurs in many words such as bon (good), son (sound) and long(long). The oral counterpart occurs in words such as beau (beautiful) and faux (false) but is in fact articulated with a higher tongue position than its nasal counterpart.
The low back unrounded nasal vowel also occurs in a number of words. They include an (year), blanc (white) and sans (without).
The nasal vowels are an important feature of the French sound system. Many languages such as English have nasal vowels which occur before a nasal, but French has fully nasalized vowels which occur without a following tautosyllabic nasal. The low mid front rounded nasal vowel has been replaced by its unrounded counterpart in a number of dialects. In this case, they have only three nasal vowels instead of four.