Closely related to the notion of liaison is that of enchaînement.  Every student of French must learn to understand the subtle difference.

In the French language the ending consonant of most words is silent.  When the following word begins with a vowel, the consonant can be pronounced as beginning that word, in essence carrying the consonant sound to the next word.  This is called liaison.  An example is the pronunciation of les amis (lay zami).

But when the consonant is not only carried forward to the next word, but also pronounced regardless whether the next word starts with a vowel, this is called enchaînement.