Phonological history of French

• The loss of almost all final consonants.
• The subsequent loss of final, which caused many newly-final consonants.
• The loss of the formerly strong stress that had characterized the language throughout much of its history and triggered many of the phonetic changes.
• Significant transformations in the pronunciation of vowels, especially nasal vowels.

Overview

• The sound of Latin short e, turning to in Proto-Romance, became ie in Old French: Latin mel, "honey" > OF miel
• The sound of Latin short o > Proto-Romance > OF uo, later ue: cor > cuor > cuer, "heart"
• Latin long ē and short i > Proto-Romance > OF ei: habēre > aveir, "to have"; this later becomes in many words, as in avoir
• Latin long ō and short u > Proto-Romance > OF ou, later eu: flōrem > flour, "flower"
• Latin a, ā > Proto-Romance > OF, probably through an intervening stage of ; mare > mer, "sea". That change also characterizes the Gallo-Italic languages of Northern Italy.

Table of vowel outcomes

• "Open" syllables, where most of the vowels were diphthongized or otherwise modified.
• Syllables followed by a palatal consonant. An usually appeared before the palatal consonant, producing a diphthong, which subsequently evolved in complex ways. There were various palatal sources: Classical Latin ; any consonant followed by a coming from Latin short or in hiatus ; or followed by or ; or followed by and preceded by, or ; or after a vowel in various sequences, such as .
• Syllables preceded by a palatal consonant. An appeared after the palatal consonant, producing a rising diphthong. The palatal consonant could arise in any of the ways just described. In addition, it could stem from an earlier brought into contact with a following consonant by loss of the intervening vowel: e.g. medietātem > Proto-Romance > Gallo-Romance > Proto-French > Old French > moitié "half".
• Nasal syllables, where nasal vowels arose. Nasal syllables inhibited many of the changes that otherwise happened in open syllables; instead, vowels tended to be raised. Subsequently, the following or was deleted unless a vowel followed, and the nasal vowels were lowered; but when the or remained, the nasal quality was lost, with no lowering of the vowel. This produced significant alternations, such as masculine fin vs. feminine fine.
• Syllables closed by followed by another consonant. By Old French times, this was "debuccalized" into, which was subsequently lost, with a phonemic long vowel taking its place. These long vowels remained for centuries, and continued to be indicated by an s, and later a circumflex, with alternations such as bette "chard" vs. bête "beast". Sometimes the length difference was accompanied by a difference in vowel quality, e.g. mal "bad" vs. mâle "male". Phonemic length disappeared by the 18th century, but the quality differences mostly remain.
• Syllables closed by followed by another consonant. The vocalized to, producing a diphthong, which then developed in various ways.
• Syllables where two or more of the above conditions occurred simultaneously, which generally evolved in complex ways. Common examples are syllables followed by both a nasal and a palatal element ; open syllables preceded by a palatal ; syllables both preceded and followed by a palatal ; syllables preceded by a palatal and followed by a nasal.

Chronological history

From Vulgar Latin through to Proto-Western-Romance

• Introduction of prosthetic short before words beginning with + consonant, becoming closed with the Romance vowel change.
• Reduction of ten-vowel system of Vulgar Latin to seven vowels; diphthongs and reduced to and ; maintenance of diphthong.
• Loss of final .
• Loss of.
• >.
• > in some words but not others.
• Final >, > .
• Vulgar Latin unstressed vowel loss: Loss of vowels between, and,.
• Reduction of and in hiatus to, followed by palatalization. Palatalization of and before front vowels.
• * is apparently doubled to prior to palatalization.
• * and become.

  To Proto-Gallo-Ibero-Romance

• and merge, becoming .
• >.
• >.
• First diphthongation : diphthongation of, to, in stressed, open syllables. That also happens in closed syllables before a palatal, often later absorbed: pēior >> > >> pire "worst"; noctem > > >> nuit; but tertium > >> tierz.
• First lenition : chain shift involving intervocalic or word-final consonants: voiced stops and unvoiced fricatives become voiced fricatives ; unvoiced stops become voiced stops. is pronounced as a single sound and voiced to, but is geminate and so is not voiced. Consonants before are lenited, also, and >. Final and when following a vowel are lenited.
• ,,, become and, respectively.
• First unstressed vowel loss: Loss of intertonic vowels except when pretonic. That occurred at the same time as the first lenition, and individual words inconsistently show one change before the other. Hence manica > manche but grānica > grange. carricāre becomes either charchier or chargier in Old French. However, in some analyses, the standard for central French was initially for lenition to occur before the unstressed vowel apocope, and patterns of the order being reversed, resulting in voiceless consonants, were loaned from the more Frankish-influenced Northern dialects of Normandy, Champagne and Lorrain, eventually spreading to some other words by analogy, leading to known cases of divergent development, such as grange and granche, and venger and vencher

  To Early Old French

• Spread and dissolution of palatalization:
• *A protected not preceded by a vowel, when stemming from an initial or from a, or when preceded by a consonant, became chiefly via palatalization then affrication: Vulgar Latin → Late Gallo-Roman → Early Old French.
• *A followed by another consonant tends to palatalize that consonant; the consonants may have been brought together by intertonic loss.
• *Palatalized sounds lose their palatal quality and eject a into the end of the preceding syllable, when open; also into the beginning of the following syllable when it is stressed, open, and front : *cugitāre > > > >> OF cuidier "to think". mansiōnātam > > > > OF maisniée "household".
• ** and eject a following normally but do not eject any preceding.
• **Double < and from various other combinations also ejects a preceding.
• **Single ejects such a, but not double, evidently since it is a double sound and causes the previous syllable to close; see comment above, under lenition.
• **Actual palatal and retain their palatal nature and don't emit preceding. Or rather, palatal does not eject a preceding ; palatal emits a preceding when depalatalized even if the preceding syllable is closed.
• **Palatal ejects a preceding as normal, but the metathesizes when a precedes, hence operārium > > >> ouvrier "worker".
• **Palatalized labials internal become palatal affricates without emitting a preceding. This development was also seen in Occitan and Ligurian.
• Second diphthongation: diphthongation of,, to,, in stressed, open syllables, not followed by a palatal sound.
• Second unstressed vowel loss: Loss of all vowels in unstressed, final syllables, except ; addition of a final, supporting when necessary, to avoid words with impermissible final clusters.
• Second lenition: Same changes as in first lenition, applied again. Losses of unstressed vowels may have blocked that change from happening.
• Palatalization of >, >.
• Further vocalic changes :
• * > .
• * >.
• Further consonant changes:
• *Geminate stops become single stops.
• *Final stops and fricatives become devoiced.
• * > unless final.
• *A is inserted between palatal, and following .
• *Palatal, are depalatalized to, when final or following a consonant.
• **In first-person verb forms, they may remain palatal when final because of the influence of the palatalized subjunctives.
• ** > when depalatalising but >, without a yod.
• Further vocalic changes :
• * >, >.
• *Diphthongs are consistently rendered as falling diphthongs, the major stress is on the first element, including for,,, etc. in contrast with the normal Spanish pronunciation.
• * >, when word-final.

  To Old French, c. 1100

• ,, lost before final,.
• > .
• >, however this is blocked if a labial consonant follows, in which case the segment remains, ultimately becoming later.
• > .
• develops allophone before, which later develops into a separate phoneme.
• Loss of and. When it results in a hiatus of with a following vowel, the becomes a schwa.
• Loss of before voiced consonant, with lengthening of preceding vowel. That produces a new set of long vowel phonemes, as is described more completely in the following section.
• >.
• Word-final, > .

  [|To Late Old French], c. 1250–1300

To Middle French, c. 1500

• au >.
• ei > .
• Loss of final consonants before a word beginning with a consonant. That produces a three-way pronunciation for many words, which is still maintained in the words six "six" and dix "ten", e.g. dix "ten" but dix amis "ten friends" and dix femmes "ten women".
• Subject pronouns start to become mandatory because of loss of phonetic differences between inflections.
• Medieval apical s, as in saint, merges into deaffricated c as in ceint, thus merging soft c and s.

  To Early Modern French, c. 1700

• Loss of most phonemically lengthened vowels.
• Loss of final consonants in a word standing alone. That produces a two-way pronunciation for many words, often still maintained: nous voyons "we see" vs. nous avons "we have". That phenomenon is known as liaison.
• oi > or . This also affects certain other instances of ; e.g. moelle, poêle.
• *The pronunciation is preserved in some forms of Quebec and Acadian French, especially by old speakers.
• Instances of /h/ were again deleted in the late seventeenth century. The phoneme /h/ had been reintroduced to the language through the absorption of loanwords, primarily of Germanic origin, in which the /h/ was preserved, and these are the /h/ instances that were lost this time around. However a Germanic h usually disallows liaison: les halles /le.al/, les haies /le.ɛ/, les haltes /le.alt/, whereas a Latin h allows liaison: les herbes /lezɛrb/, les hôtels /lezotɛl/.

  To Modern French, c. 2000

• becomes a uvular sound: trill or fricative .
• Merger of with in the 18th century
• Loss of final. Loss of elsewhere unless a sequence of three consonants would be produced. Meridional French tend to be more conservative.
• Gradual loss of liaison, unless absolutely needed, such as to distinguish quelques-uns from quelqu'un.
• In Metropolitan French, gradual merging of and, both are realized as, but the distinction is maintained in Meridional French, Swiss French, Belgian French and Quebec French.
• In Metropolitan French, loss of the phoneme, merged with, both are realized as, but the distinction is maintained in Swiss French, Belgian French and Quebec French.
• In Metropolitan French, loss of the phoneme, merged with, both are realized as, but the distinction is maintained in Quebec French.
• In Metropolitan French, loss of the phoneme, merged with, both are realized as, but the distinction is maintained in Swiss French, Belgian French and Quebec French.
• In Metropolitan French, merger of into when word-final, but the distinction is maintained in Belgian French.

  Nasalization

• Nasalization of,, before or .
• Nasalization occurs before and blocks the changes > and >. However, the sequence occurs because has more than one origin: coin "corner" <. The sequences or, and or, also occur, but the last two occur in only one word each, in each case alternating with a non-diphthongized variant: om or uem, and bon or buen. The version without the diphthong apparently arose in unstressed environments and is the only one that survived.
• Lowering of and to but not in the sequences and : bien, plein. The realization of to probably occurred during the 11th or early 12th century and did not affect Old Norman or Anglo-Norman. Ultimately merged into.
• Nasalization of,, before or.

• Lowering of > >.
• Denasalization of vowels before or followed by a vowel or semi-vowel.
• Deletion of or after remaining nasal vowels : dent "tooth" < < OFr dent < EOFr <.

• > > > . That also affects diphthongs such as > > ; > >, ; > >,. Also, >, ; >,.
• > >, but the sound is maintained in Quebec French.
• > >
• > . In the 20th century, this sound has low functional load and has tended to merge with.