Liaison and Enchaînement
In French, there is a tendency to link together words within the rhythm group. This takes three forms: a) elision, discussed here; b) enchaînement and c) liaison.
To understand the concept of enchaînement ("linking"), consider the following group of words: ma petite amie [maptitami] . Enchaînement can be defined as "the inclusion of a word final pronounced consonant (like the /t/ of petite) in the first syllable of a following vowel-intial word" (like the /a/ of amie). The syllabic division of ma petite amie is as follows: [ma-pti-ta-mi] . Here we see that the third syllable (-ta-) starts with the final consonant of the word petite, followed by the /a/ of amie. In other words, we place consonants in syllables within the rhythm group according to the same rules as used in individual words. That is what enchaînement is.
Note that though enchaînement is characteristic of French, it is fairly rare in English. For example one says a big apple and NOT a bi gapple
The absence of English enchaînement is also evident in the following:
a) a nice statue
b) an ice statue
Since enchaînement is not characteristic of English, it is possible to hear the difference between these two noun phrases. In other words, "n" of an in b) is not pronounced as if it belonged to the first syllable of the following word (ice). If English did use enchaînement, we couldn't tell the difference between a) and b)!
When speaking French, be sure to use enchaînement if the context requires it (i.e.: when a consonant-final word is followed by a vowel within the rhythm group).
Liaison implies enchaînement, but there is a slight difference. By definition, liaison is:
"the pronunciation of a word-final, silent letter before a word that begins with a vowel".
So, for example, the "s" of Ils is silent if you say the word Ils [il] by itself or if the following word begins with a consonant (e.g.: ils parlent = [ilpaʁl] . However, when the next word begins with a vowel, as in ils ont, [ilzõ] the "s" represents the consonant /z/. That's what liaison is! And, remember, liaison implies enchaînement, so the syllabic division of [ilzõ] is [il-zõ].
Now the challenge is that not all word-final, silent consonants get pronounced when a vowel follows. In fact, there are three relevant scenarios: a) cases where liaison is mandatory; b) cases where liaison is impossible; and c) cases where liaison is optional. Let's first consider mandatory cases.
Liaison is required when there is a strong relationship between the two words (so always within a rhythm group). Here are the main kinds:
a) determiner + noun or adjective: les_enfants [lezãfã] , nos_élèves [nozelɛv] , les_anciens combattants [lezãsjɛ̃kõbatã] .
b) pronoun + verb: ils_aiment [ilzɛm] , Marie les_aime, [maʁilezɛm] . Note that this is also true of inverted structures, e.g.: Peut-il venir? [pøtilvəniʁ] .
c) adjective + noun: petit_enfant [pətitãfã]
d) mononsyllabic adverb + adjective, e.g.: très_intéressant [tʁɛzɛ̃teʁesã] .
e) preposition + noun: en_Europe [ãnøʁɔp] , chez_eux [ʃezø] (however there no liaison if chez is followed by a proper nouns, e.g.: chez Anne [ʃean] ).
Examples where liaison does not occur usually involve words belonging to different rhythm groups (you can review the rules for rhythm group division here). The main categories are as follow:
a) between words joined by et and mais, e.g.: Elle semble gentille et / intelligente; Paul s'amusait, mais / il a dû partir.
b) between a non-pronominal subject + verb: e.g.: Les enfants / arrivent.
c) between a singular noun and a following adjective, e.g.: un cas / intéressant; un enfant / écossais.
d) after interrogative quand, e.g.: Quand / est-il parti?
Note however that liaison does occur between quand and est-ce que, par ex.: Quan*d*_est-ce qu'il vient? In this case the "d" is actually pronounced as /t/.
In same cases, liaison may or may not occur. When liaison does occur in a context where it is optional, it is usually an indication that the situation in which the speaker finds herself is relatively formal. The following are the main examples of optional liaison:
a) following avoir and être, e.g.: Ils l'ont(_)aimé [ilõ(t)eme], je suis intelligent [ʒəsɥi(z)ɛ̃teliʒã].
b) plural noun + adjective, e.g.: des_amis(_)intimes [dezami(z)ɛ̃tim], des gens intéressants [deʒã(z)ɛ̃teʁesã].
c) following forms of pouvoir, vouloir, aller or devoir, e.g.: elle peut(_)aider [ɛlpø(t)ede], je vais insister [ʒəvɛ(z)ɛ̃siste].
d) following a polysyllabic adverb, e.g.: beaucoup(_)à faire [boku(p)afɛʁ].
Note that within the category of optional liaison, some are more likely than others, e.g.: a) above is more common than d). Cases involving third person forms of être, e.g.: Il est ici [ilɛtisi] are very common indeed, though still classified by reference works as "optional".
• Liaison only occurs before a vowel.
• There is never liaison before words beginning with "h-aspiré", e.g.: les hiboux [leibu].
• Liaison never occurs after the word et.