Assimilation - French Pronunciation

Changes in French consonant sounds due to assimilation

Assimilation is a pronunciation phenomenon which causes consonant sounds to change according to the sounds that surround them. More specifically, assimilation occurs when voiced and unvoiced sounds are combined. Because it can be difficult to pronounce voiced and unvoiced sounds together, one or the other is assimilated: either a normally voiced consonant becomes unvoiced or a normally unvoiced consonant becomes voiced.

Voicing - La Sonorité

Voiced sounds (les sons sonores) occur when the vocal cords vibrate, while unvoiced consonants (les consonnes sourdes) are pronounced without vibrating the vocal cords. To understand the difference, place your hand on your Adam's apple and say D and T. You should feel your vocal cords vibrate with the first sound but not the second.

The voiced French consonants and sounds are B, D, G, J, L, M, N, R, V, Z, and all vowels.

The unvoiced French consonant sounds are CH, F, K, P, S, and T.

All unvoiced consonants have a voiced equivalent; i.e., the pairs are pronounced in the same place in the mouth/throat but the first is unvoiced while the second is voiced:

  • CH - J
    F - V
    K - G
    P - B
    S - Z
    T - D


Assimilation occurs when voiced and unvoiced sounds meet, either in a single word or in a phrase.
When a voiced consonant is found next to an unvoiced one, the voiced consonant usually becomes unvoiced due to assimilation.
This type of assimilation almost always occurs in the consonant pairs BS and BT (click the words to hear them pronounced):BS and BT are the most common groups that cause voiced to unvoiced assimilation, but there are a few other words that follow the same pattern, such as médecin [may tseh(n)].

It is also possible, although less common, for unvoiced sounds to become voiced. This type of assimilation occurs most commonly with unvoiced consonants found between two vowels. Because the vowels must be voiced, the consonant sounds become voiced as well. The letter X, which is usually pronounced [ks], changes to [gz] when found between vowels: exact [eh gzakt]. Likewise, the word seconde is pronounced [seu go(n)d] rather than [seu ko(n)d].