It is pronounced, but only in those cases when a liaison is required and then its pronunciation is not the expected one (/s/) but /z/.
- Je suis allé dans ce magasin. /ʒə sɥizale dɑ̃…/
The liaison is required before vowel sounds but not before semi-vowels sounds (/j/, /ɥ/, /w/).
(« […] généralement, en français, les semi-voyelles ne donnent pas lieu à élision ou liaison. », réf.)
The semi-vowels in French and typical words in which they are found
/j/, comme dans yeux [jø], fille [fij], abeille [abɛj];
/ɥ/ comme dans huile [ɥil], lui [lɥi] ;
/w/ comme dans oui [wi], jouet [ʒwɛ], moi [mwa].
There are a great number of exceptions and some cases when it is not considered to be an error not to make a liaison although certain people think it is better to respect those liaisons. Here is a good introduction to the question of liaisons: liaisons.
Examples
-
Je suis au téléphone, ne me dérange pas. /ʒə sɥizo te.le.fɔn…/
-
Je suis oisif. /ʒə sɥi wa.zif/
-
Je suis ailleurs. /ʒə sɥiza.jœʁ/
It follows then that in “je suis optimiste” the s is pronounced, just as in “très optimiste”.
- /ʒə sɥizɔp.ti.mist/
- /tʁɛzɔp.ti.mist/
A word ending with a consonant followed by a word starting with a vowel is necessary but not sufficient for a liaison.
This rules out any liaison in:
Je suis très sociable. Neither the final s of suis, nor the final s of très is pronounced.
That doesn’t mean final consonants are never pronounced in French. There are many words where they are, but this is unrelated to your question.
A potential liaison belongs to one of three groups:
- Mandatory liaisons. Not doing them is considered a mistake whatever the language register.
Les avions (the planes). Always pronounced with a liaison, no exception.
Je suis très optimiste. Liaison may be missed in colloquial relaxed French, depending on the speaker.
- Optional liaisons. These are more often realized in formal than in colloquial speech.
This group is the larger one:
Je suis une personne. My impression is that a liaison is often not realized.
- Forbidden ones. Realizing such a liaison is considered a mistake.
Le président autrichien.
Note that what group a liaison belongs to is not set in stone. There have been changes in the past and there are a few ongoing ones.
For example Wikipedia states the liaison after très is optional but in other sources, e.g. BDL and FLE, it is mandatory.
Finally, note that semi-vowels are definitely compatible with liaisons, e.g.:
/j/ Dans tes yeux. (mandatory liaison)
/ɥ/ Une sauce sans huile. (mandatory liaison)
/w/ Il respire avec ses ouïes (mandatory liaison)
As usual, there are exceptions:
Les oui et les non (forbidden liaison1)
Also, note that an h can influence the liaison, depending on whether its an aspirated h ("h aspiré") or not. Both are silent, but the aspirated h prevents the liaison. Normal rules apply if the h is not aspirated.
Des histoires (not aspirated, liaison)
Des hiboux (aspirated, no liaison)
You can find the complete list of words with an aspirated h on the wikipedia page.
1 Oui behaves exactly as if it had started with an aspirated H: "Houi"
Leave a comment