Numbers aloud: cinq, six, huit, dix, neuf, vingt
Summary
Several French numbers change their final consonant depending on what follows: pronounced in full when counting alone, often reduced before a consonant, and linked by liaison before a vowel.
Explanation
A handful of French numbers — cinq, six, huit, dix, neuf, vingt — behave like little chameleons: their final consonant is pronounced differently depending on three environments: in isolation (counting, or at the end of a phrase), before a word starting with a consonant, and before a word starting with a vowel sound, where liaison links the consonant onto the next syllable.
cinq is /sɛ̃k/ when counting or alone. Before a consonant, careful traditional pronunciation drops the /k/ (cinq minutes /sɛ̃ minyt/), though many speakers today keep it (/sɛ̃k minyt/) — both are heard. Before a vowel, cinq keeps its /k/, which resyllabifies onto the next word: cinq ans /sɛ̃k‿ɑ̃/.
six and dix pattern together. Alone, they are /sis/ and /dis/. Before a consonant, the final consonant is dropped and the vowel shortens: six livres /si livʁ/, dix minutes /di minyt/. Before a vowel, liaison surfaces a /z/: six amis /si.z‿ami/, dix ans /di.z‿ɑ̃/.
huit is /ɥit/ both alone and before a vowel, where the /t/ carries over: huit heures /ɥi.t‿œʁ/. Before a consonant, the /t/ is dropped: huit jours /ɥi ʒuʁ/. neuf is /nœf/ almost everywhere — alone, before a consonant, before most vowels — except in two frozen liaison phrases where the f voices to /v/: neuf ans /nœv‿ɑ̃/ and neuf heures /nœv‿œʁ/.
vingt is /vɛ̃/ both alone and before a consonant (vingt minutes /vɛ̃ minyt/); before a vowel it takes a liaison /t/: vingt ans /vɛ̃.t‿ɑ̃/. Inside the compounds 21–29, that t is pronounced outright, not just in liaison: vingt-deux /vɛ̃t.dø/, vingt-trois /vɛ̃t.tʁwa/. Two more numbers worth knowing here: cent takes a liaison /t/ before a vowel (cent ans /sɑ̃.t‿ɑ̃/), and deux/trois take a liaison /z/ (deux heures /dø.z‿œʁ/); sept is invariable, always /sɛt/ in every environment; and un takes a liaison /n/ before a vowel (un an /œ̃.n‿ɑ̃/).
In short: treat each number's final consonant as having up to three faces — a full "citation" form used alone, a reduced or dropped form before a consonant (for cinq, six, dix, huit), and a liaison form before a vowel that often changes the consonant's sound (s/x → /z/, d → /t/, f → /v/ in neuf ans/heures) or simply carries the number's own final consonant across (vingt‿ans, huit‿heures). Learning the exceptions — neuf ans/heures, and vingt-deux keeping its t outright — pays off because they are extremely high-frequency words.
Examples
Il est cinq heures. — It is five o'clock. (/il‿ɛ sɛ̃k‿œʁ/ — cinq keeps its /k/ before the vowel of heures.)
J'ai six frères et six amis. — I have six brothers and six friends. (six frères /si fʁɛʁ/ before a consonant; six amis /si.z‿ami/ with liaison /z/ before a vowel.)
Le magasin ferme dans huit jours, à huit heures. — The shop closes in eight days, at eight o'clock. (huit jours /ɥi ʒuʁ/ (no t) vs huit heures /ɥi.t‿œʁ/ (t carried by liaison).)
Le train arrive à neuf heures, dans neuf minutes. — The train arrives at nine o'clock, in nine minutes. (neuf heures /nœv‿œʁ/ (f voiced to v) vs neuf minutes /nœf minyt/ (plain f).)
Elle a vingt ans et son frère en a vingt-deux. — She is twenty and her brother is twenty-two. (vingt ans /vɛ̃.t‿ɑ̃/ (liaison t) vs vingt-deux /vɛ̃t.dø/ (t pronounced outright inside 21–29).)
Il y a cent ans, on comptait le temps différemment. — A hundred years ago, time was counted differently. (cent ans /sɑ̃.t‿ɑ̃/ — liaison /t/ before the vowel.)
Common mistakes
Il a vingt-t-ans.
Il a vingt ans.
Vingt links to a following vowel with a liaison /t/, so vingt ans is pronounced roughly "vin-tan". Hearing that /t/, learners sometimes write it in as an extra letter, but liaison is pronounced, never written: the spelling stays vingt ans, with the linking sound existing only in speech.
Prerequisites
Related rules
liaisonnumbersconnected-speech