History of French

French is a Romance language that specifically is classified under the Gallo-Romance languages.
The discussion of the history of a language is typically divided into "external history", describing the ethnic, political, social, technological, and other changes that affected the languages, and "internal history", describing the phonological and grammatical changes undergone by the language itself.

External social and political history

Roman Gaul (''Gallia'')

Before the Roman conquest of what is now France by Julius Caesar, much of present France was inhabited by Celtic-speaking people referred to by the Romans as Gauls and Belgae. Southern France was also home to a number of other remnant linguistic and ethnic groups including Iberians along the eastern part of the Pyrenees and western Mediterranean coast, the remnant Ligures on the eastern Mediterranean coast and in the alpine areas, Greek colonials in places such as Marseille and Antibes, and Vascones and Aquitani in much of the southwest. The Gaulish-speaking population is held to have continued speaking Gaulish even as considerable Romanisation of the local material culture occurred, with Gaulish and Latin coexisting for centuries under Roman rule and the last attestation of Gaulish to be deemed credible having been written in the second half of the 6th century about the destruction of a pagan shrine in Auvergne.
The Celtic population of Gaul had spoken Gaulish, which is moderately well attested and appears to have wide dialectal variation including one distinctive variety, Lepontic. The French language evolved from Vulgar Latin, but it was strongly influenced by Gaulish in its grammar. Examples include sandhi phenomena, the loss of unstressed syllables and the vowel system. Syntactic oddities attributable to Gaulish include the intensive prefix ro- ~ re-, emphatic structures, prepositional periphrastic phrases to render verbal aspect and the semantic development of oui "yes", aveugle "blind".
Some sound changes are attested: → and → appears in a pottery inscription from la Graufesenque in which the word paraxsidi is written for paropsides. Similarly, the development -cs- → → and -ct- → →, the latter being common to much of Romance languages">Romance language">Romance languages, also appears in inscriptions: Divicta ~ Divixta, Rectugenus ~ Rextugenus ~ Reitugenus, and is present in Welsh, e.g. *seχtan → saith "seven", *eχtamos → eithaf "extreme". For Romance, compare:

Latin fraxinus "ash " → OFr fraisne, Occitan fraisse, Catalan freixe, Portuguese freixo, Romansch fraissen.
Latin lactem "milk" → French lait, Welsh llaeth, Portuguese leite, Catalan llet, Piemontese lait, Liguro leite.

Both changes sometimes had a cumulative effect in French: Latin capsa → *kaχsa → caisse or captīvus → *kaχtivus → Occitan caitiu, OFr chaitif.
In French and the adjoining folk dialects and closely related languages, some 200 words of Gaulish origin have been retained, most of which pertaining to folk life. They include:

land features ;
plant names ;
wildlife ;
rural and farm life, most notably: boue "mud", cervoise "ale", charrue "plow", glaise "loam", gord "kiddle, stake net", jachère "fallow field", javelle "sheaf, bundle, fagot", marne "marl", mouton "sheep", raie "lynchet", sillon "furrow", souche "tree stump, tree base", tarière "auger, gimlet", tonne "barrel";
some common verbs.; and
loan translations: aveugle "blind", from Latin ab oculis "eyeless", calque of Gaulish exsops "blind", literally "eyeless".

Other Celtic words were not borrowed directly but brought in through Latin, some of which had become common in Latin, braies "knee-length pants", chainse "tunic", char "dray, wagon", daim "roe deer", étain "tin", glaive "broad sword", manteau "coat", vassal "serf, knave". Latin quickly took hold among the urban aristocracy for mercantile, official and educational reasons but did not prevail in the countryside until some four or five centuries later since Latin was of little or no social value to the landed gentry and peasantry. This eventual spread of Latin can be attributed to social factors in the Late Empire such as the movement from urban-focused power to village-centred economies and legal serfdom.

Franks

In the 3rd century, Western Europe started to be invaded by Germanic tribes from the north and the east, and some of the groups settled in Gaul. In the history of the French language, the most important groups are the Franks in much of northern France, the Alemanni in the modern German/French border area, the Burgundians in the Rhône Valley, the Suebi in the Spanish autonomous community of Galicia and Northern Portugal, the Vandals in Southern Andalusia, and the Visigoths in much of southern France as well as Spain. The Frankish language had a profound influence on the Latin spoken in their respective regions by altering both the pronunciation and the syntax. It also introduced a number of new words. Sources disagree on how much of the vocabulary of modern French comes from Germanic words and range from just 500 words to 15% of the modern vocabulary to even higher if Germanic words coming from Latin and other Romance languages are taken into account.
Changes in lexicon/morphology/syntax:

The name of the language itself, français, comes from Old French franceis/francesc from the Germanic frankisc "french, frankish" from Frank. The Franks referred to their land as Franko, which became Francia in Latin in the 3rd century. The name Gaule was also taken from the Frankish *Walholant.
Several terms and expressions associated with their social structure.
Military terms.
Colours derived from Frankish and other Germanic languages.
Other examples among common words are abandonner, arranger, attacher, auberge, bande, banquet, bâtir, besogne, bille, blesser, bois, bonnet, bord, bouquet, bouter, braise, broderie, brosse, chagrin, choix, chic, cliché, clinquant, coiffe, corroyer, crèche, danser, échaffaud, engage, effroi, épargner, épeler, étal, étayer, étiquette, fauteuil, flan, flatter, flotter, fourbir, frais, frapper, gai, galant, galoper, gant, gâteau, glisser, grappe, gratter, gredin, gripper, guère, guise, hache, haïr, halle, hanche, harasser, héron, heurter, jardin, jauger, joli, laid, lambeau, layette, lécher, lippe, liste, maint, maquignon, masque, massacrer, mauvais, mousse, mousseron, orgueil, parc, patois, pincer, pleige, rat, rater, regarder, remarquer, riche/richesse, rime, robe, rober, saisir, salon, savon, soupe, tampon, tomber, touaille, trépigner, trop, tuyau and many words starting with a hard g or with an aspired h
Endings in -ard, -aud, -an/-and all very common family name affixes for French names.
Endings in -ange, diminutive -on
Many verbs ending in -ir such as affranchir, ahurir, choisir, guérir, haïr, honnir, jaillir, lotir, nantir, rafraîchir, ragaillardir, tarir, etc.
The prefix mé-
The prefix for-, four- as in forbannir, forcené, forlonger, fourvoyer, etc. from Frankish fir-, fur- merged with Old French fuers "outside, beyond" from Latin foris. Latin foris was not used as a prefix in Classical Latin, but appears as a prefix in Medieval Latin following the Germanic invasions.
The prefix en-, em- was extended to fit new formations not previously found in Latin. Influenced or calqued from Frankish *in- and *an-, usually with an intensive or perfective sense: emballer, emblaver, endosser, enhardir, enjoliver, enrichir, envelopper:
The syntax shows the systematic presence of a subject pronoun in front of the verb, as in the Germanic languages: je vois, tu vois, il voit. The subject pronoun is optional, function of the parameter pro-drop, in most other Romance languages.
The inversion of subject-verb to verb-subject to form the interrogative is characteristic of the Germanic languages but is not found in any major Romance language, except Venetian and French.
The adjective placed in front of the noun is typical of Germanic languages. The word order is more frequent in French than in the other major Romance languages and is occasionally compulsory. When it is optional, it can change the meaning: grand homme and le plus grand homme vs. homme grand and l'homme le plus grand, certaine chose vs. chose certaine. In Walloon, the order "adjective + noun" is the general rule, as in Old French and North Cotentin Norman.
Several words are calqued or modelled on corresponding terms from Germanic languages.

Frankish had a determining influence on the birth of Old French, which partly explains that Old French is the earliest-attested Romance language, such as in the Oaths of Strasbourg and Sequence of Saint Eulalia. The new speech diverged so markedly from the Latin that it was no longer mutually intelligible. The Old Low Frankish influence is also primarily responsible for the differences between the langue d'oïl and langue d'oc since different parts of Northern France remained bilingual in Latin and Germanic for several centuries, which correspond exactly to the places in which the first documents in Old French were written. Frankish shaped the popular Latin spoken there and gave it a very distinctive character compared to the other future Romance languages. The very first noticeable influence is the substitution of a Germanic stress accent for the Latin melodic accent, which resulted in diphthongisation, distinction between long and short vowels and the loss of the unaccentuated syllable and of final vowels: Latin decima > F dîme ; Vulgar Latin dignitate > OF deintié ; VL catena > OF chaiene. On the other hand, a common word like Latin aqua > Occitan aigue became Old French ewe > F eau 'water' and was likely influenced by the OS or OHG word pronunciation aha.
In addition, two new phonemes that no longer existed in Vulgar Latin returned: and, e.g. VL altu > OF halt 'high' ; VL vespa > F guêpe 'wasp' ; L viscus > F gui 'mistletoe' ; LL vulpiculu 'little fox' > OF gupil. Italian and Spanish words of Germanic origin borrowed from French or directly from Germanic also retained and : It, Sp. guerra 'war'. These examples show a clear result of bilingualism, which frequently altered the initial syllable of the Latin.
There is also the converse example in which the Latin word influenced the Germanic word: framboise 'raspberry' from OLF *brambasi conflated with LL fraga or OF fraie 'strawberry', which explains the shift to from, and in turn the final -se of framboise turned fraie into fraise.
Philologists such as Pope estimate that perhaps 15% of the vocabulary of Modern French still derives from Germanic sources, but the proportion was larger in Old French, as the language was re-Latinised and partly Italianised by clerics and grammarians in the Middle Ages and later. Nevertheless, many such words like haïr "to hate" and honte "shame" remain common.
Urban T. Holmes Jr. estimated that German was spoken as a second language by public officials in western Austrasia and Neustria as late as the 850s and that it had completely disappeared as a spoken language from those regions only in the 10th century, but some traces of Germanic elements still survive, especially in dialectal French.

Normans and terms from the Low Countries

In 1204 AD, the Duchy of Normandy was integrated into the Crown lands of France, and many words were introduced into French from Norman of which about 150 words of Scandinavian origin are still in use. Most of the words are about the sea and seafaring: abraquer, alque, bagage, bitte, cingler, équiper, flotte, fringale, girouette, guichet, hauban, houle, hune, mare, marsouin, mouette, quille, raz, siller, touer, traquer, turbot, vague, varangue, varech. Others pertain to farming and daily life: accroupir, amadouer, bidon, bigot, brayer, brette, cottage, coterie, crochet, duvet, embraser, fi, flâner, guichet, haras, harfang, harnais, houspiller, marmonner, mièvre, nabot, nique, quenotte, raccrocher, ricaner, rincer, rogue.
Likewise, most words borrowed from Dutch deal with trade or are nautical in nature: affaler, amarrer, anspect, bar, bastringuer, bière, blouse, botte, bouée, bouffer, boulevard, bouquin, cague, cahute, cambuse, caqueter, choquer, diguer, drôle, dune, équiper, frelater, fret, grouiller, hareng, hère, lamaneur, lège, manne, mannequin, maquiller, matelot, méringue, moquer, plaque, sénau, tribord, vacarme, as are words from Low German: bivouac, bouder, homard, vogue, yole, and English of this period: arlequin, bateau, bébé, bol, bouline, bousin, cliver, chiffe/chiffon, drague, drain, est, groom, héler, lac, merlin, mouette, nord, ouest, potasse, rade, rhum, sonde, sud, turf, yacht.

Langue d'oïl

The medieval Italian poet Dante, in his Latin De vulgari eloquentia, classified the Romance languages into three groups by their respective words for "yes": Nam alii oc, alii si, alii vero dicunt oil, "For some say oc, others say si, others say oïl". The oïl languagesfrom Latin , "that is it"occupied northern France, the oc languagesfrom Latin ', "that"southern France, and the si languagesfrom Latin ', "thus"the Italian and Iberian Peninsulas. Modern linguists typically add a third group within France around Lyon, the "Arpitan" or "Franco-Provençal language", whose modern word for "yes" is ouè.
The Gallo-Romance group in the north of France, the langue d'oïl like Picard, Walloon and Francien, were influenced by the Germanic languages spoken by the Frankish invaders. From the time period of Clovis I, the Franks extended their rule over northern Gaul. Over time, the French language developed from either the Oïl language found around Paris and Île-de-France or from a standard administrative language based on common characteristics found in all Oïl languages.
Langue d'oc used oc or òc for "yes" and is the language group in the south of France and northernmost Spain. The languages, such as Gascon and Provençal, have relatively little Frankish influence.
The Middle Ages also saw the influence of other linguistic groups on the dialects of France.
Modern French, which was derived mainly from the langue d'oïl, acquired the word si to contradict negative statements or respond to negative questions, from cognate forms of "yes" in Spanish and Catalan, Portuguese, and Italian.
From the 4th to the 7th centuries, Brythonic-speaking peoples from Cornwall, Devon and Wales travelled across the English Channel for reasons of trade and of flight from the Anglo-Saxon invasions of England. They established themselves in Armorica, and their language became Breton in more recent centuries, which gave French bijou "jewel" and menhir.
Attested since the time of Julius Caesar, a non-Celtic people who spoke a Basque-related language inhabited the Novempopulania in southwestern France, but the language gradually lost ground to the expanding Romance during a period spanning most of the Early Middle Ages. Proto-Basque influenced the emerging Latin-based language spoken in the area between the Garonne and the Pyrenees, which eventually resulted in the dialect of Occitan called Gascon. Its influence is seen in words like boulbène and cargaison.
Vikings from Scandinavia invaded France from the 9th century onwards and established themselves mostly in what would be called Normandy. The Normans took up the langue d'oïl spoken there, but Norman French remained heavily influenced by Old Norse and its dialects. They also contributed many words to French related to sailing and farming.
After the 1066 Norman Conquest of England, the Normans' language developed into Anglo-Norman, which served as the language of the ruling classes and commerce in England until the Hundred Years' War, when the use of French-influenced English had spread throughout English society.
Around then, many words from Arabic entered French, mainly indirectly through Medieval Latin, Italian and Spanish. There are words for luxury goods, spices, trade goods, sciences, and mathematics. It was only after the 19th-century development of French colonies in North Africa that French borrowed words directly from Arabic.

Modern French

For the period until around 1300, some linguists refer to the oïl languages collectively as Old French. The earliest extant text in French is the Oaths of Strasbourg from 842; Old French became a literary language with the chanson de geste that told tales of the paladins of Charlemagne and the heroes of the Crusades.
The first notarized document in Modern French was redacted in Aosta in 1532, when in Paris Latin was still in use. The first government authority to adopt Modern French as official was the Aosta Valley in 1536, three years before France itself. By the Ordinance of Villers-Cotterêts in 1539 King Francis I made French the official language of administration and court proceedings in France, which ousted Latin, which had been used earlier. With the imposition of a standardised chancery dialect and the loss of the declension system, the dialect is referred to as Middle French. The first grammatical description of French, the Tretté de la Grammaire française by Louis Maigret, was published in 1550. Many of the 700 words of Modern French that originate from Italian were introduced in this period, including several denoting artistic concepts, luxury items and food. The earliest history of the French language and its literature was also written in this period: the Recueil de l'origine de la langue et poesie françoise, by Claude Fauchet, published in 1581.
Following a period of unification, regulation and purification, the French of the 17th and the 18th centuries is sometimes referred to as Classical French, but many linguists simply refer to French language from the 17th century to today as Modern French.
The foundation of the Académie française in 1634 by Cardinal Richelieu created an official body whose goal has been the purification and preservation of the French language. The group of 40 members is known as the Immortals, not, as some erroneously believe, because they are chosen to serve for the extent of their lives, but because of the inscription engraved on the official seal given to them by their founder Richelieu: À l'immortalité. The foundation still exists and contributes to the policing of the language and to the adaptation of foreign words and expressions. Some recent modifications include the change from software to logiciel, packet-boat to paquebot, and riding-coat to redingote. The word ordinateur for computer, however was created not by the Académie but by a linguist appointed by IBM.
From the 17th to the 19th centuries, France was the leading land power in Europe; together with the influence of the Enlightenment, French was therefore the lingua franca of educated Europe, especially with regards to the arts, literature and diplomacy. Monarchs like Frederick II of Prussia and Catherine the Great of Russia spoke and wrote in excellent French. The Russian, German and Scandinavian courts spoke French as their main or official language and regarded their national languages as the language of the peasants. The spread of French to other European countries was also aided by emigration of persecuted Huguenots.
In the 17th and the 18th centuries, French established itself permanently in the Americas. There is an academic debate about how fluent in French the colonists of New France were. Less than 15% of colonists were from the Paris region and presumably spoke French, but most of the rest came from north-western and western regions of France in which French was not the usual first language. It is not clearly known how many among those colonists understood French as a second language, and how many among them, nearly all of whom natively spoke an oïl language, could understand and be understood by those who spoke French because of interlinguistic similarity. In any case, such a linguistic unification of all the groups coming from France happened that many sources noted that all "Canadiens" spoke French natively by the end of the 17th century, well before the unification was complete in France. Today, French is the language of about 10 million people in the Americas.
Through the Académie, public education, centuries of official control and the media, a unified official French language has been forged, but there remains a great deal of diversity today in terms of regional accents and words. For some critics, the "best" pronunciation of the French language is considered to be the one used in Touraine, but such value judgments are fraught with problems, and with the ever-increasing loss of lifelong attachments to a specific region and the growing importance of the national media, the future of specific "regional" accents is often difficult to predict. The French nation-state, which appeared after the 1789 French Revolution and Napoleon I's empire, unified the French people in particular through the consolidation of the use of the French language. Hence, according to the historian Eric Hobsbawm, "the French language has been essential to the concept of 'France', although in 1789 50% of the French people did not speak it at all, and only 12 to 13% spoke it 'fairly' – in fact, even in oïl language zones, out of a central region, it was not usually spoken except in cities, and, even there, not always in the faubourgs . In the North as in the South of France, almost nobody spoke French." Hobsbawm highlighted the role of conscription, invented by Napoleon, and of the 1880s public instruction laws, which allowed to mix the various groups of France into a nationalist mold, which created the French citizen and his consciousness of membership to a common nation, and the various patois were progressively eradicated.

Issues

There is some debate in today's France about the preservation of the French language and the influence of English, especially with regard to international business, the sciences and popular culture. There have been laws enacted to require all print ads and billboards with foreign expressions to include a French translation and to require quotas of French-language songs on the radio. There is also pressure, in differing degrees, from some regions as well as minority political or cultural groups for a measure of recognition and support for their regional languages.
Once the key international language in Europe, being the language of diplomacy from the 17th to the mid-20th centuries, French lost most of its international significance to English in the 20th century, especially after World War II, with the rise of the United States as a dominant global superpower. A watershed was the Treaty of Versailles, which ended World War I and was written in both French and English. A small but increasing number of large multinational firms headquartered in France use English as their working language even in their French operations. Also, to gain international recognition, French scientists often publish their work in English.
Those trends have met some resistance. In March 2006, President Jacques Chirac briefly walked out of an EU summit after Ernest-Antoine Seilliere began addressing the summit in English. In February 2007, Forum Francophone International began organising protests against the "linguistic hegemony" of English in France and in support of the right of French workers to use French as their working language.
French remains the second most-studied foreign language in the world, after English, and is a lingua franca in some regions, notably in Africa. The legacy of French as a living language outside Europe is mixed: it is nearly extinct in some former French colonies, but the language has changed to creoles, dialects or pidgins in the French departments in the West Indies even though its people are educated in Standard French. On the other hand, many former French colonies have adopted French as an official language, and the total number of French speakers has increased, especially in Africa.
In the Canadian province of Quebec, different laws have promoted the use of French in administration, business and education since the 1970s. Bill 101, for example, obliges most children whose parents did not attend an English-speaking school to be educated in French. Efforts are also made such as by the Office québécois de la langue française to reduce the variation of French spoken in Quebec and to preserve the distinctiveness of Quebec French.
There has been French emigration to the United States, Australia and South America, but the descendants of those immigrants have been so assimilated that few of them still speak French. In the United States, efforts are ongoing in Louisiana and parts of New England to preserve French there.

Internal phonological history

French has radically transformative sound changes, especially compared to other Romance languages such as Spanish, Portuguese, Italian and Romanian:

Latin	Written French	Spoken French	Italian	Catalan	Spanish	Portuguese	Romanian
"dog"	chien		cane	ca	can	cão	câine
"eight"	huit		otto	vuit	ocho	oito	opt
"pear"	poire		pera	pera	pera	pera	pară
"to help"	aider		aiutare	ajudar	ayudar	ajudar	ajuta
"it lies "	gît		giace	jeu	yace	jaz	zace

Language	Change	Form	Pronun.
Classical Latin	–
Vulgar Latin	Vowel length is replaced by vowel quality
Western Romance	vowel changes, first lenition	sabudo
Gallo-Romance	loss of final vowels	sabud
	second lenition	savuḍ
	final devoicing	savuṭ
	loss of /v/ near rounded vowel	seüṭ
Old French	fronting of /u/	seüṭ
	loss of dental fricatives	seü
French	collapse of hiatus	su

Language	Change	Form	Pronun.
Classical Latin	–
Vulgar Latin	Vowel length is replaced by vowel quality
Western Romance	vowel changes, first lenition	vida
Old French	second lenition, final /a/ lenition to /ə/	viḍe
	loss of dental fricatives	vie
French	loss of final schwa	vie

Vowels

The Vulgar Latin underlying French and most other Romance languages had seven vowels in stressed syllables, and five in unstressed syllables. Portuguese and Italian largely preserve that system, and Spanish has innovated only in converting to and to, which resulted in a simple five-vowel system. In French, however, numerous sound changes resulted in a system with 12–14 oral vowels and 3–4 nasal vowels.
Perhaps the most salient characteristic of French vowel history is the development of a strong stress accent, which is usually ascribed to the influence of the Germanic languages. It has led to the disappearance of most unstressed vowels and to pervasive differences in the pronunciation of stressed vowels in syllables that were open or closed syllables. It is commonly thought that stressed vowels in open syllables were lengthened, and most of the long vowels were then turned into diphthongs. The loss of unstressed vowels, particularly those after the stressed syllable, ultimately produced the situation in Modern French in which the accent is uniformly found on the last syllable of a word.

Unstressed vowels

Vulgar Latin had five vowels in unstressed syllables:. When they occurred word-finally, all were lost in Old French except for, which turned into a schwa :

Latin	Vulgar Latin	French
"done "		faite
"night"		nuit
"I said"		dis
"eight"		huit
"done "		fait

A final schwa also developed when the loss of a final vowel produced a consonant cluster that was then unpronounceable word-finally, usually consisting of a consonant followed by l, r, m or n :

"people" > peuple
"between" > VL * > entre
"father" > père
"donkey" > OF asne > âne
"island" > OF isle > île

The final schwa was eventually lost as well but has left its mark in the spelling and in the pronunciation of final consonants, which normally remain pronounced if a schwa followed but are often lost otherwise: fait "done " vs. faite "done ".
Intertonic vowels were lost entirely except for a in a syllable preceding the stress, which became a schwa. The stressed syllable is underlined in the Latin examples:

"people" > peuple
"donkey, ass" > OF asne > âne
"angel" > ange
"priest" > VL * > OF prestre > prêtre
"fourteen" > VL * > quatorze
"Stephen" > VL * > OF Estievne > Étienne
"week" > VL * > semaine
* "to speak" > VL * > parler
"sacrament" > OF sairement > serment "oath"
"to help" > aider
"to break one's fast" > OF disner > dîner "to dine"

Stressed vowels

As noted [|above], stressed vowels developed quite differently depending on whether they occurred in an open syllable or a closed syllable. In open syllables, the Vulgar Latin mid vowels all diphthongized, becoming Old French ie oi ue eu respectively, while Vulgar Latin was raised to Old French e. In closed syllables, all Vulgar Latin vowels originally remained unchanged, but eventually, merged into, became the front rounded vowel and was raised to.
This table shows the outcome of stressed vowels in open syllables:

Vulgar Latin	Old French	Modern French spelling	Modern French pronunciation	Examples
	e	e, è	,	"sea" > mer, "such" > tel, "nose" > nez, "born" > né
	ie	ie	,	"yesterday" > hier, * "honey" > miel, "foot" > pied
	oi	oi		pear > poire, "hair" > poil, "way" > voie
	i	i		"wire" > fil, "life" > vie
	ue	eu, œu	,	* "heart" > OF cuer > cœur, "new" > OF nuef > neuf
	eu	eu, œu	,	"hour" > heure, "throat" > gueule
	u	u		"hard" > dur

This table shows the outcome of stressed vowels in closed syllables:

Vulgar Latin	Old French	Modern French spelling	Modern French pronunciation	Examples
	a	a		"part" > part, "carriage" > char, "cow" > vache
	e	e		"land" > terre, "seven" > VL > OF set > sept
	e	e		dry > sec
	i	i		"estate" > ville "town"
	o	o	,	"port" > port, "foolish" > sot
	o	ou		"short" > court, "drop " > OF gote > goutte
	u	u		"none" > nul

Nasal vowels

Latin that ended up not followed by a vowel after the loss of vowels in unstressed syllables was ultimately absorbed into the preceding vowel, which produced a series of nasal vowels. The developments are somewhat complex. There are two separate cases, depending on whether the originally stood between vowels or next to a consonant. See the article on the phonological history of French for full details.

Long vowels

Latin before a consonant ultimately was absorbed into the preceding vowel, which produced a long vowel. For the most part, the long vowels are no longer pronounced distinctively long in Modern French. In most cases, the formerly-long vowel is pronounced identically to the formerly short vowel, but some pairs are distinguished by their quality.
A separate later vowel lengthening operates allophonically in Modern French and lengthens vowels before the final voiced fricatives .

Effect of palatalised consonants

Late Vulgar Latin of the French area had a full complement of palatalised consonants, and more developed over time. Most of them, if preceded by a vowel, caused a sound to appear before them, which combined with the vowel to produce a diphthong and eventually developed in various complex ways. A also appeared after them if they were originally followed by certain stressed vowels in open syllables. If the appearance of the sound produced a triphthong, the middle vowel was dropped.
Examples show the various sources of palatalized consonants:

From Latin or in hiatus:
* "to lower" > VL * > OF baissier > baisser
* "palace" > VL * > palais
From Latin or followed by a front vowel :
* "peace" > VL * > paix
* "wax" > VL * > * > cire
From Latin sequences such as,, :
* "done" > Western Vulgar Latin * > fait
* "to release" > Western Vulgar Latin * > OF laissier > laisser "to let"
* "black" > Western Vulgar Latin * > Early Old French neir > noir
* "night" > Western Vulgar Latin * > * > * nuit
From Latin or followed by except after a vowel:
* "dog" > pre-French * > chien
* "to load" > Western Vulgar Latin * > * > pre-French * > OF chargier
From Latin consonantal :
* "worse" > Western Vulgar Latin * > pre-French * > pire
* "he lies " > pre-French * > * > OF gist > ''gît''

Effect of ''l''

In Old French, l before a consonant became u and produced new diphthongs, which eventually resolved into monophthongs: "false" > fausse. See the article on the phonological history of French for details.

Consonants

The sound changes involving consonants are less striking than those involving vowels. In some ways, French is actually relatively conservative. For example, it preserves initial pl-, fl-, cl-, unlike Spanish, Portuguese and Italian: "to rain" > pleuvoir.

Lenition

Consonants between vowels were subject to a process called lenition, a type of weakening. That was more extensive in French than in Spanish, Portuguese or Italian. For example, between vowels went through the following stages in French: > > > no sound. However, in Spanish only the first two changes happened; in Brazilian Portuguese, only the first change happened, and in Italian, no change happened. Compare "life" > vie with Italian vita, Portuguese vida, Spanish vida. This table shows the outcomes:

Vulgar Latin	French	Examples
,	no sound	"life" > vie; "to fall" > OF cheoir > choir
,	or no sound	"to pay" > payer; "to put, to lease" > louer "to rent"
,,,	or no sound	* "to be wise" > savoir "to know"; "to have to" > devoir; * "known" > OF seü > su
		"cause" > chose "thing"
		"drink" > VL * > poison "poison"

Palatalization

As described above, Late Vulgar Latin of the French area had an extensive series of palatalized consonants that developed from numerous sources. The resulting sounds tended to drop a /j/ before and/or after them, which formed diphthongs that later developed in complex ways.
Latin and in hiatus position developed into /j/ in Vulgar Latin and then combined with the preceding consonant to form a palatalized consonant. All consonants could be palatalized in that fashion. The resulting consonants developed as follows :
followed by or developed into Vulgar Latin *, which was lenited to * between vowels. The pronunciation was still present in Old French but was later simplified to :

"hundred" > cent
"to please" > plaisir "pleasure"
"peace" > OF pais > paix

before or developed originally into Vulgar Latin *, which subsequently became when it was not between vowels. The pronunciation was still present in Old French but was later simplified to. Between vowels, often disappeared:

"people" > gents > gents
"queen" > OF reïne > reine
"forty" > quarante
"to read" > pre-French * > lire

and before except after a vowel developed into and, respectively. Both and persisted the Old French but were later subsequently simplified to and :

"chariot" > char
"leg" > jambe
"sleeve" > * > manche
"dry " > sèche

In various consonant combinations involving or + another consonant, the or developed into /j/, which proceeded to palatalize the following consonant:

"done" > fait
"to release" > OF laissier "to let" > laisser
"old" > > OF vieille
"joint" > VL */arteklu/ > orteil "toe"
"to keep watch" > OF veillier > veiller

In some cases, the loss of an intertonic vowel led to a similar sequence of /j/ or palatalized consonant + another consonant, which was palatalized in turn:

"half" > */mejjetate/ > */mejtʲat/ > moitié
"to think" >> * > */kujetare/ > Western Vulgar Latin */kujedare/ > pre-French */kujdʲare/ > OF cuidier > cuider
* "household" > OF maisniée
* "to worsen" > OF ''empoirier''

Changes to final consonants

As a result of the pre-French loss of most final vowels, all consonants could appear word-finally except and, which were always followed by at least a schwa, stemming from either a final or a prop vowel. In Old French, however, all underlying voiced stops and fricatives were pronounced voiceless word-finally. That was clearly reflected in Old French spelling: the adjectives froit "cold", vif "lively", larc "large" and the verbs, je doif "I must" vs. ils doivent "they must", je lef "I may wash" vs. ils levent "they wash". Most of the alternations have since disappeared, but the adjectival alternation vif vs. vive has remained.
In the Middle French, most final consonants became gradually lost. That proceeded in stages:

The loss of final consonants when appearing before another word beginning with a consonant. This stage is preserved in the words six and dix, which are pronounced standing alone but before a word beginning with a consonant and before a word beginning with a vowel. If the word ended in a stressed vowel followed by /s/, the same process apparently operated as elsewhere when an /s/ preceded a consonant, with a long vowel resulting.
Loss of final consonants before a pause. That left a two-way pronunciation for most words, with final consonants pronounced before a following vowel-initial word but not elsewhere, and is the origin of the modern phenomenon of liaison.
Loss of final consonants in all circumstances. The process is still ongoing, which causes a gradual loss of liaison, especially in informal speech, except in certain limited contexts and fixed expressions.

The final consonants that are normally subject to loss are,,, sometimes and, rarely . The consonants and were normally preserved, but,, and did not occur. A more recent countervailing tendency, however, is the restoration of some formerly-lost final consonants, as in sens, now pronounced but formerly, as still found in the expressions sens dessus dessous "upside down" and sens devant derrière "back to front". The restored consonant may stem from the liaison pronunciation or the spelling, and it serves to reduce ambiguity. For example, is also the pronunciation of cent "hundred", sang "blood" and sans "without".

Effect of substrate and superstrate languages

French is noticeably different from most other Romance languages. Some of the changes have been attributed to substrate influence, which is from Gaulish, or superstrate influence, which is from Frankish. In practice, it is difficult to say with confidence which sound and grammar changes were caused by substrate and superstrate influences, since many of the changes in French have parallels in other Romance languages or are changes that are undergone by many languages in their process of development. However, the following are likely candidates.
In phonology:

The reintroduction of the consonant at the beginning of a word is caused by Frankish influence and occurs mostly in words borrowed from Germanic. The sound no longer exists in Standard Modern French, but a Germanic h usually disallows liaison: les halles, les haies, les haltes, but a Latin h allows liaison: les herbes, les hôtels.
The reintroduction of in Northern Norman, Picard, Walloon, Champenois, Bourguignon and Bas-Lorrain is caused by Germanic influence. All Romance languages have borrowed Germanic words containing, but all languages south of the isogloss, including the ancestor of Modern French, converted it to, which usually developed subsequently into. English has borrowed words from Norman French and Standard French, which sometimes results in doublets like warranty and guarantee or warden and guardian.
The occurrence of an extremely-strong stress accent led to the loss of unstressed vowels and the extensive modification of stressed vowels, which is likely caused by Frankish influence and possibly Celtic influence since both languages had a strong initial stress This feature also no longer exists in Modern French, but its influence remains in the uniform final word stress in Modern French since the strong stress caused all vowels after it to be ultimately lost.
Nasalization resulting from compensatory vowel lengthening in stressed syllables was caused by Germanic and/or Celtic stress accent. Among Romance languages, it occurs primarily in French, Occitan, Arpitan and Portuguese, all of which have possible Celtic substratums. However, scattered dialects of Romance languages, including Sardinian, Spanish and Lombard, also have the phenomenon as an allophonic property. Among the four Romance languages in which it is prominent beyond divergent dialects, the only one for which it is undebatably phonemic is French
The development of front-rounded vowels,, and may be caused by Germanic influence, as few Romance languages other than French have such vowels, but Gallo-Romance languages have them and share a Germanic influence. At least one sound,, still exists in Celtic languages. A number of other scholars, most famously including Romance linguist Ascoli, have attributed the French sound to the Celtic substratum. The attribution of the sounds to Celtic influence actually predates the emergence of academic linguistics as early as the 1500s, when it was attested as being called "Gaulish u". Among Romance languages, its distribution strongly correspondent with areas of suspected Celtic substratum: French, Arpitan, Occitan, Romansch and Gallo-Italic dialects, along with some dialects of Portuguese. The change may have occurred around the same time as a similar fronting of long to in the British Celtic languages. On the other hand, scholars such as Posner and Meyer-Lübke acknowledge the possibility of Celtic influence but see the development as internally motivated.
The lenition of intervocalic consonants may be caused by Celtic influence. A similar change happened in Celtic languages about the same time, and the demarcation between Romance dialects with and without this change corresponds closely to the limit of Celtic settlement in ancient Rome. The lenition also affected words that were borrowed from Germanic royer < *, which suggests that the tendency persisted for some time after it had been introduced.
The devoicing of word-final voiced consonants in Old French was caused by Germanic influence.

In other areas:

Various words may have shifted gender under the influence from words of the same meaning or with a similar sound in Gaulish, as a result of the Celtic substrate. A connectionist model predicting shifts in gender assignment for common nouns more accurately predicted historical developments when the Gaulish genders of the same words were considered in the model. The loss of the neuter may have been accelerated in French also because Gaulish neuters were very hard to distinguish and were possibly lost earlier than Latin neuters. In comparison, Romanian retains the neuter gender and Italian retains it for a couple of words. Portuguese, Sardinian, Catalan and Spanish also retain remnants of the neuter outside nouns in demonstrative pronouns and the like, but they have lost the neuter for nouns.
The development of verb-second syntax in Old French in which the verb must come in the second position in a sentence, regardless of whether the subject precedes or follows the verb, was probably caused by Germanic influence.
The first-person plural ending -ons is likely derived from the Frankish termination -ōmês, -umês.
The use of the letter k in Old French, which was replaced by c and qu during the Renaissance, was caused by Germanic influence. Typically, k was not used in Latin and other Romance languages. Similarly, the use of w and y also diminished.
The impersonal pronoun on "one, you, they" but more commonly replacing nous "we" in colloquial French, from Old French om, a reduced form of homme "man", was a calque of the Germanic impersonal pronoun man "one, you, they" reduced form of mann "man".
The expanded use of avoir "to have" over the more customary use of tenir "to have, hold" in other Romance languages was likely the influence from the Germanic word for "have", which has a similar form.
The increased use of auxiliary verbal tenses, especially the passé composé, is probably caused by Germanic influence. Unknown in Classical Latin, the passé composé begins to appear in Old French in the early 13th century, after the Germanic and the Viking invasions. Its construction is identical to the one seen in all other Germanic languages at the time and earlier: "verb "be" + past participle" when there is movement, indication of state or change of condition but ""have" + past participle" for all other verbs. The passé composé is not universal to the Romance language family since only languages known to have Germanic superstrata display that type of construction, and they do so in varying degrees. The languages nearest to Germanic areas show constructions most similar to those seen in Germanic. Italian, Spanish and Catalan are other Romance languages with this type of compound verbal tense.
The heightened frequency of si in Old French correlates to Old High German so and thanne; and the construction of French aussi is likely a calque or borrowing of the Frankish *allswā.
The tendency in Old French to use adverbs to complete the meaning of a verb, as in lever sur, monter en amont, aller avec, traire avant, etc., is likely to be of Germanic origin.
The lack of a future tense in conditional clauses is likely caused by Germanic influence.
Pre-Roman Celtic languages in Gaul also made use of a vigesimal system, but it largely vanished early in French linguistic history or became severely marginalised in its range. The Nordic vigesimal system may possibly derive ultimately from the Celtic. Old French also had treis vingts, cinq vingts.