Vulgar Latin (in Latin, sermo vulgaris, "folk speech") is a blanket term covering the popular dialects and sociolects of the Latin language which diverged from each other in the early Middle Ages, evolving into the Romance languages by the 9th century. The terms Vulgar Latin and Late Latin are often used synonymously. Vulgar Latin can also refer to vernacular speech from other periods, including the Classical period, in which case it may also be called Popular Latin.
Spoken Latin differed from literary Latin in its pronunciation, vocabulary, and grammar, though some of its features did not appear until the late Empire. Other features are likely to have been present much earlier in spoken Latin.
During the Middle Ages, Vulgar Latin coexisted with a more classically structured form of the language used by scholars, scribes and the clergy in formal settings, but lacking any native speakers, called Medieval Latin.
The name "vulgar" simply means "folk", derived from the Latin word vulgaris, meaning "of people". "Vulgar Latin" has a variety of meanings:
Most definitions of "Vulgar Latin" define it as the spoken, rather than written, language. It is important to remember that "Vulgar Latin" is an abstract term, not the name of any particular dialect. The term itself predates the field of sociolinguistics, and research into the history of Vulgar Latin was in some ways a precursor to sociolinguistics. The latter studies language variation associated with social variables, and tends not to view variation as a strict standard–non-standard dichotomy (for example, Classical–Vulgar Latin) but as variations. In light of fields such as sociolinguistics, dialectology, and historical linguistics, Vulgar Latin is the sociological, geographical and historic variations in Latin that excludes the speech and the writings of the educated classes. It is because there are so many types of variation that definitions of Vulgar Latin differ so much.
Because the daily speech of Latin speakers was not transcribed, Vulgar Latin can only be studied indirectly. Knowledge of Vulgar Latin comes from three chief sources: First, the comparative method reconstructs the underlying forms from the attested Romance languages, and notes where they differ from Classical Latin; second, various prescriptive grammar texts from the Late Latin period condemn linguistic errors that Latin speakers were liable to commit, giving us an idea of how Latin was spoken; third, the solecisms and non-Classical usages that occasionally are found in Late Latin texts also reveal, in part, the author's spoken language.
Some literary works written in a lower register of Latin also provide a glimpse into the world of early Vulgar Latin. The works of Plautus and Terence, being comedies with many characters who were slaves, preserve basilectal Latin features, as does the recorded speech of freedmen in the Cena Trimalchionis by Petronius Arbiter.
For many centuries after the fall of the Roman Empire in the West, Vulgar Latin continued to coexist with a written form of Late Latin, Medieval Latin; for when speakers of Romance vernaculars set out to write with correct grammar and spelling, they attempted to emulate the norms of Classical Latin. This scholarly Latin, "frozen" by Justinian's codifications of Roman law on the one hand, and by the Catholic Church on the other, was eventually unified by the medieval copyists; it continued to exist as a Dachsprache in the Middle Ages, and a lingua franca well beyond them.
Vulgar Latin developed differently in the various provinces of the Roman Empire, gradually giving rise to such languages as French, Catalan, Italian, Spanish, Portuguese, Romanian and several dozen other languages. Although the official language in these areas was Latin, Vulgar Latin was popularly spoken until the new localized forms diverged sufficiently from Latin, thus emerging as separate languages. However, despite the widening gulf between the spoken and written Latin, throughout the imperial era and until the 8th century CE, it was not significant enough as to make them mutually unintelligible. József Herman states:
Indeed, at the third Council of Tours in 813, priests were ordered to preach in the vernacular language — either in the rustica lingua romanica (Vulgar Latin), or in the Germanic vernaculars — since the common people could no longer understand formal Latin. Within a generation, the Oaths of Strasbourg (842), a treaty between Charlemagne's grandsons Charles the Bald and Louis the German, was proffered and recorded in a language that was already distinguished from Latin. Consider the excerpt below:
From this point on, the Latin vernaculars began to be treated as separate languages in practice, developing local norms and orthographies of their own, and "Vulgar Latin" ceases to be a useful term.
|Classical Latin||Vulgar Latin||English|
Certain words from Classical Latin were dropped from the vocabulary. Classical equus, "horse", was consistently replaced, by caballus "nag" (but note Romanian iapă, Sardinian èbba, Spanish yegua, Catalan euga and Portuguese égua all meaning "mare" and deriving from Classical equa).
A sample of words that are exclusively Classical, and those that were productive in Romance, is to be found in the table to the right.
The vocabulary changes affected even the basic grammatical particles of Latin; there are many that vanish without a trace in Romance, such as an, at, autem, donec, enim, ergo, etiam, haud, igitur, ita, nam, postquam, quidem, quin, quod, quoque, sed, utrum and vel.
Verbs with prefixed prepositions frequently displaced simple forms. The number of words formed by such suffixes as -bilis, -arius, -itare and -icare grew apace. These changes occurred frequently to avoid irregular forms or to regularise genders.
On the other hand, since Vulgar Latin and Latin proper were for much of their history different registers of the same language, rather than different languages, some Romance languages preserve Latin words that were lost in most others. For example, Italian ogni ("each/every") preserves Latin omnes. Other languages use cognates of totus for the same meaning; for example tutto in Italian, tudo/todo in Portuguese, todo in Spanish, tot in Catalan, tout in French and tot in Romanian.
Sometimes, a classical Latin word was kept alongside a Vulgar Latin word. In Vulgar Latin, classical caput, "head", yielded to testa (originally "pot") in some forms of western Romance, including French and Italian. But Italian, French and Catalan kept the Latin word under the form capo, chef, and cap which retained many metaphorical meanings of "head", including "boss". The Latin words with the original meanings are preserved in Romanian cap, meaning 'head' in the anatomical sense, together with ṭeastă, meaning skull or carapace. Southern Italian dialects likewise preserve capo as the normal word for "head". Spanish and Portuguese have cabeza/cabeça, derived from *capetia, a modified form of caput, while in Portuguese testa was retained as the word for "forehead".
Frequently, words borrowed directly from literary Latin at some later date, rather than evolved within Vulgar Latin, are found side by side with the evolved form: the lack of expected phonetic developments is a clue that a word has been borrowed. For example, Vulgar Latin fungus, "fungus, mushroom", which became Italian fungo, Catalan fong, and Portuguese fungo, became hongo in Spanish, showing the f > h shift that was common in early Spanish (cf. filius > Spanish hijo, "son", facere > Spanish hacer, "to do"). But Spanish also had fungo, which by its lack of the expected sound shift shows that it was borrowed directly from Latin.
Vulgar Latin contained a large number of words of foreign origin not present in literary texts. Many works on medicine were written and distributed in Greek, and words were often borrowed from these sources. For example, gamba ('knee joint' ), originally a veterinary term only, replaced the classical Latin word for leg (crus) in most Romance languages. (cf. Fr. jambe, It. gamba). Cooking terms were also often borrowed from Greek sources, a calque based on a Greek term was ficatum (iecur) (goose's liver fattened with figs), with the participle ficatum becoming the common word for liver in Vulgar Latin (cf. Sp. higado, Fr. foie, Pt. fígado, It. fegato, Romanian ficat). Important religious terms were also drawn from religious texts written in Greek, such as episcopus (bishop), presbyter (priest), martyr etc. Words borrowed from Gaulish include caballus (horse) and carrus (chariot).
Insight into the vocabulary changes of late Vulgar Latin in France can be seen in the Reichenau Glosses, written on the margins of a copy of the Vulgate Bible, suggesting that the 4th-century Vulgate words were no longer readily understood in the 8th century, when the glosses were likely written. These glosses demonstrate typical vocabulary changes in Gallo-Romance.
The Reichenau Glosses show vocabulary replacement:
Germanic loan words:
And words whose meaning has changed:
Many of the forms castigated in the Appendix Probi proved to be the productive forms in Romance; oricla (Classical Latin auricula) is the source of French oreille, Catalan orella, Spanish oreja, Italian orecchia, Romanian ureche, Portuguese orelha, "ear", not the Classical Latin form.
Several other consonants were "softened", especially in intervocalic position (an instance of diachronic lenition):
|Evolution of the stressed vowels in Vulgar Latin|
|ў||short Y||[y] > [ɪ]||[e]||ẹ|
|ȳ||long Y||[yː] > [iː]||[i]||y, i|
|æ||AE||[ai] > [ɛ]||[ɛ]||ę|
|œ||OE||[oi] > [e]||[e]||ẹ|
|au||AV||[au]||[au] > [o]||au, ọ|
|1 Traditional academic transcription in Latin and Romance studies, respectively.|
There is evidence that in the imperial period all the short vowels except a differed by quality as well as by length from their long counterparts. So, for example ē was pronounced close-mid /eː/ while ĕ was pronounced open-mid /ɛ/, and ī was pronounced close /iː/ while ĭ was pronounced near-close /ɪ/. The diphthongs ae and oe, pronounced /ai/ and /oi/ in earlier Latin, had also begun their monophthongisation to /ɛ/ and /e/, respectively. Oe was always a rare diphthong in Classical Latin; in Old Latin, oinos (one) regularly became unus.
As Vulgar Latin evolved, three main changes occurred in parallel. First, length distinctions were lost, so that for instance ă and ā came to be pronounced the same way. Second, the near-close vowels ĭ and ŭ became more open in most varieties of Vulgar Latin, merging with the long vowels ē and ō, respectively. As a result, Latin pira "pear" (fruit) and vēra "true", came to rhyme in most of its daughter languages: Italian, French, and Spanish pera, vera; Old French poire, voire. Similarly, Latin nux ("nut", acc. sing) and vōx (voice) become Italian noce, voce, Portuguese noz, voz, and French noix, voix (in some cases the quality of the vowel later changed again, because of regularising tendencies, or other extraneous influences).
There was likely some regional variation in pronunciation, as the Eastern Romance languages and the Southern Romance languages evolved differently. In Sardinian, for instance, ĭ and ŭ became more close, merging with their long counterparts ī and ū. Apart from Sardinian, which preserved the position of the Classical Latin vowels but lost phonemic vowel length, what happened to Vulgar Latin can be summarized as in the table to the right. More precisely, these mergers happened in most of western Europe, yielding the seven vowel system of Italo-Western-Romance.
In general, though, the ten-vowel system of Classical Latin (not counting the Greek letter y), which relied on phonemic vowel length, was newly modelled into one in which vowel length distinctions lost phonemic importance, and qualitative distinctions of height became more prominent. (Exceptions were Friulian, and some dialects of French, which have retained a contrast between long and short vowels.)
In Vulgar Latin, the stress on accented syllables became much more pronounced than in Classical Latin. This tended to cause unaccented syllables to become less distinct, while working further changes on the sounds of the accented syllables. The results of short o and e in stressed position proved to be unstable in several of the Romance languages, with a tendency to break up into diphthongs. Focus, "fireplace", became the general word in Vulgar Latin for "fire" (replacing ignis), but its short o sound became a diphthong — a different diphthong — in many languages:
In French and Italian, these changes occurred only in open syllables. Spanish, however, diphthongised in all circumstances, resulting in a simple five-vowel system in both stressed and unstressed syllables. Romanian shows diphthongisation of short e (fier from Latin ferrum, "iron") but not of short o (foc). In Portuguese, no diphthongisation occurred at all (ferro, fogo).
Some languages experienced further mergers, reducing the number of stressed vowels down from seven (to six in Romanian, to five in Sardinian and Spanish). On the other hand, later monophthongisations led to new vowel phonemes in some languages (such as [y], [œ], and [ø] in French), while nasalisation produced new phonemic nasal vowels in French and Portuguese.
Latin au was under some pressure to change in the Roman Republican period; a number of populist politicians adopted the spelling Clodius for the well known Roman name Claudius, but this change was not universal, and marked as basilectal well into the early Empire. Au was initially retained, but was eventually reduced in many languages to [o]. (Portuguese evolved only as far as [ou] until much more recently; Occitan and Romanian preserve [au] to this day.) The results of Latin ae were also subject to at least some early variation; French proie (spoils) presumes [e] rather than [ɛ] from Classical Latin praeda.
There was more variability in the result of the unstressed vowels. Two main paths can be distinguished:
In Catalan, the process was similar to that of Portuguese in that the short Latin o turned into an open vowel, but short e eventually turned into a closed [e] in Western dialects (opposite to the pattern in the other Italo-Western languages), and a schwa in the Eastern ones. This schwa slowly evolved towards an open [ɛ], although in most of the Balearic Islands the schwa is maintained even today. Eastern dialects have some vocalic instability similar to that of Portuguese as well: unstressed [e] and [a] turn into a schwa (at some point of the evolution of the language, this change did not affect [e] in pre-stressed position, a pronunciation that can still be heard in part of the Balearics), and, except in most of Majorca, unstressed [o] and [u] merge into [u].
Definite articles formerly were demonstrative pronouns or adjectives; compare the fate of the Latin demonstrative adjective ille, illa, (illud), in the Romance languages, becoming French le and la, Catalan and Spanish el and la, and Italian il and la. The Portuguese articles o and a are ultimately from the same source. Sardinian went its own way here also, forming its article from ipse, ipsa (su, sa); some Catalan and Occitan dialects have articles from the same source. While most of the Romance languages put the article before the noun, Romanian has its own way, by putting the article after the noun, eg. lupul ("the wolf") and omul ("the man" — from lupus ille and *homo ille), a result of its membership in the Balkan linguistic union.
This demonstrative is used in a number of contexts in some early texts in ways that suggest that the Latin demonstrative was losing its force. The Vetus Latina Bible contains a passage Est tamen ille dæmon sodalis peccati ("The devil is a companion of sin"), in a context that suggests that the word meant little more than an article. The need to translate sacred texts that were originally in Greek, which had a definite article, may have given Christian Latin an incentive to choose a substitute. Aetheria uses ipse similarly: per mediam vallem ipsam ("through the middle of the valley"), suggesting that it too was weakening in force.
Another indication of the weakening of the demonstratives can be inferred from the fact that at this time, legal and similar texts begin to swarm with prædictus, supradictus, and so forth (all meaning, essentially, "aforesaid"), which seem to mean little more than "this" or "that". Gregory of Tours writes, Erat autem. . . beatissimus Anianus in supradicta civitate episcopus ("Blessed Anianus was bishop in that city.") The original Latin demonstrative adjectives were felt no longer to be specific enough. In less formal speech, reconstructed forms suggest that the inherited Latin demonstratives were made more forceful by being compounded with ecce (originally an interjection: "behold!"), which also spawned Italian ecco. This is the origin of Old French cil (*ecce ille), cist (*ecce iste) and ici (*ecce hic); Spanish aquel and Portuguese aquele (*eccu ille); Italian questo (*eccu iste), quello (*eccu ille) and obsolescent codesto (*eccu tibi iste); Spanish acá and Portuguese cá, (*ecce hic), Portuguese acolá (*ecce illic) and aquém (*ecce inde); Romanian acest (*ecce iste) and acela (*ecce ille), and many other forms.
On the other hand, even in the Oaths of Strasbourg, no demonstrative appears even in places where one would clearly be called for in all the later languages. (pro Deo amur — "for the love of God") Using the demonstratives as articles may have still been too slangy for a royal oath in the 9th century. Considerable variation exists in all of the Romance vernaculars as to their actual use: in Romanian, the articles can be suffixed to the noun, as in other members of the Balkan linguistic union and the North Germanic languages.
The numeral unus, una (one) supplies the indefinite article in all cases. This is anticipated in Classical Latin; Cicero writes cum uno gladiatore nequissimo ("with a most immoral gladiator"). This suggests that unus was beginning to supplant quidam in the meaning of "a certain" or "some" by the 1st century BCE.
The three grammatical genders of Classical Latin were replaced by a two-gender system in most Romance languages. In Latin, gender is partly a matter of inflection, i.e. there are different declensional paradigms associated with the masculine, the feminine, and the neuter, and partly a matter of agreement, i.e. nouns of a certain gender require forms of the same gender in adjectives and pronouns associated with them.
The loss of these final consonants led to a remodelling of the gender system. In Classical Latin, the endings -us and -um distinguished masculine from neuter nouns in the second declension; with both -s and -m gone, the neuters merged with the masculines, a process that is complete in Romance. By contrast, some neuter plurals such as gaudia, "joys", were re-analysed as feminine singulars. The loss of the final m was a process which seems to have begun by the time of the earliest monuments of the Latin language. The epitaph of Lucius Cornelius Scipio Barbatus, who died around 150 BCE, reads TAVRASIA CISAVNA SAMNIO CEPIT, which in Classical Latin would be Taurāsiam, Cisaunam, Samnium cēpit, "He captured Taurasia, Cisauna, and Samnium". (Note that in the Latin alphabet, the letters u and v, i and j were not distinguished until the early modern period. Upper-case u and j did not exist, while lower-case j and v were only graphic variations of i and u, respectively.)
The neuter gender of classical Latin was in most cases absorbed by the masculine both syntactically and morphologically. The syntactical confusion starts already in the Pompeian graffiti, e.g. cadaver mortuus for cadaver mortuum "dead body" and hoc locum for hunc locum "this place" (-us was normally a masculine ending, and -um a neuter ending). The morphological confusion shows primarily in the adoption of the nominative ending -us (-Ø after -r) in the o-declension: in Petronius Arbiter, we find balneus for balneum "bath", fatus for fatum "fate", caelus for caelum "heaven", amphiteatrus for amphitheatrum "amphitheatre" and conversely the nominative thesaurum for thesaurus "treasure".
In modern Romance languages, the nominative s-ending has been abandoned and all substantives of the o-declension have an ending derived from -UM > -u/-o/-Ø: MURUM > Italian, Portuguese, and Spanish muro, Catalan and French mur and CAELUM > Italian, Spanish cielo, French ciel, Portuguese céu, Catalan cel, Sardinian kelu. Old French still had -s in the nominative and -Ø in the accusative in both original genders (murs, ciels).
For some neuter nouns of the third declension, the oblique stem was the productive form in Romance; for others, the nominative/accusative form, which was identical in Classical Latin, was the one that survived. Evidence suggests that the neuter gender was under pressure well back into the imperial period. French (le) lait, Catalan (la) llet, Spanish (la) leche, Portuguese (o) leite, Italian (il) latte, and Romanian lapte(le) ("milk"), all derive from the non-standard but attested Latin nom./acc. neut. lacte or acc. masc. lactem. Note also that in Spanish the word became feminine, while in French, Portuguese and Italian it became masculine (in Romanian it remained neuter, lapte/lăpturi). Other neuter forms, however, were preserved in Romance; Catalan and French nom, Portuguese and Italian nome ("name") all preserve the Latin nominative/accusative nomen, rather than the oblique stem form *nominem (which nevertheless produced Spanish nombre).
|Typical Italian endings|
|Nouns||Adj. & determiners|
Most neuter nouns had plural forms ending in -A or -IA; some of these were reanalysed as feminine singulars, such as gaudium ("joy"), plural gaudia; the plural form lies at the root of the French feminine singular (la) joie, as well as of Catalan and Occitan (la) joia (Italian la gioia is a borrowing from French); the same for lignum ("wood stick"), plural ligna, that originated the Catalan feminine singular noun (la) llenya, and Spanish (la) leña. Some Romance languages still have a special form derived from the ancient neuter plural which is treated grammatically as feminine: e.g. BRACCHIUM : BRACCHIA "arm(s)" > Italian (il) braccio : (le) braccia, Romanian braț(ul) : brațe(le). Cf. also Merovingian Latin ipsa animalia aliquas mortas fuerant.
Alternations such as l'uovo fresco ("the fresh egg") / le uova fresche ("the fresh eggs") in Italian are usually analysed as masculine in the singular and feminine in the plural, with an irregular plural in -a (heteroclisis). However, it is also consistent with their historical development to say that uovo is simply a regular neuter noun (< ovum, plural ova) and that the characteristic ending for words agreeing with these nouns is -o in the singular and -e in the plural. Thus, neuter nouns can arguably be said to persist in Italian, and also Romanian.
These formations were especially common when they could be used to avoid irregular forms. In Latin, the names of trees were usually feminine, but many were declined in the second declension paradigm, which was dominated by masculine or neuter nouns. Latin pirus ("pear tree"), a feminine noun with a masculine-looking ending, became masculine in Italian (il) pero and Romanian păr(ul); in French and Spanish it was replaced by the masculine derivations (le) poirier, (el) peral; and in Portuguese and Catalan by the feminine derivations (a) pereira, (la) perera. Fagus ("beech"), another feminine noun ending in -us, is preserved in some languages as a masculine, e.g. Romanian fag(ul) or Catalan (el) faig; other dialects have replaced it with its adjectival forms fageus or fagea ("made of beechwood"), whence Italian (il) faggio, Spanish (el) haya, and Portuguese (a) faia.
As usual, irregularities persisted longest in frequently used forms. From the fourth declension noun manus ("hand"), another feminine noun with the ending -us, Italian and Spanish derived (la) mano, Catalan (la) mà, and Portuguese (a) mão, which preserve the feminine gender along with the masculine appearance.
Except for the Italian and Romanian heteroclitic nouns, other major Romance languages have no trace of neuter nouns, but all have vestigial, semantically neuter pronouns. French: celui-ci, celle-ci, ceci; Spanish: éste, ésta, esto (all meaning "this"); Italian: gli, le, ci ("to him", "to her", "to it"); Catalan: ho, açò, això, allò ("it", this, this/that, that over there); Portuguese: todo, toda, tudo ("all of him", "all of her", "all of it"); Venetian: 'sto qua, 'sta qua, questo (meaning "this") and qûeło là, qûeła là, queło=queła (meaning "that").
In Spanish, a three-way contrast is also made with the definite articles el, la, and lo. The last is used with nouns denoting abstract categories: lo bueno, literally 'the good' or 'that which is good', from bueno: good; "lo importante", i.e. that which is important. "¿Sabes lo tarde que es?", literally "Do you know 'the late' that it is?", or more idiomatically "Do you know how late it is?", from tarde: late. This is traditionally interpreted as the existence of a neuter gender in Spanish, although no morphological distinction is made anywhere else but in the singular definite article.
Some varieties of Astur-Leonese maintain endings for the three genders such as follows: bonu, bona, bono ("good").
The complete elimination of case happened only gradually. Old French still maintained a nominative/oblique distinction (called cas-sujet/cas-régime); this disappeared in the course of the 12th or 13th centuries, depending on the dialect. Old Occitan also maintained a similar distinction, as did many of the Rhaeto-Romance languages until only a few hundred years ago. Romanian still preserves a separate genitive/dative case along with vestiges of a vocative case.
The distinction between singular and plural was marked in two ways in the Romance languages. North and west of the La Spezia-Rimini line, which runs through northern Italy, the singular was usually distinguished from the plural by means of final -s, which was present in the old accusative plurals in masculine and feminine nouns of all declensions. South and east of the La Spezia-Rimini Line, the distinction was marked by changes of final vowels, as in contemporary standard Italian and Romanian. This preserves and generalizes distinctions that were marked on the nominative plurals of the first and second declensions.
As Latin was losing its case system, prepositions started to move in to fill the void. In colloquial Latin, the preposition ad followed by the accusative was sometimes used as a substitute for the dative case.
Just as in the disappearing dative case, colloquial Latin sometimes replaced the disappearing genitive case with the preposition de followed by the ablative.
The verb forms were much less affected by the phonetic losses that eroded the noun case systems; indeed, an active verb in Spanish (or other modern Romance language) will still strongly resemble its Latin ancestor. One factor that gave the system of verb inflections more staying power was the fact that the strong stress accent of Vulgar Latin, replacing the light stress accent of Classical Latin, frequently caused different syllables to be stressed in different conjugated forms of a verb. As such, although the word forms continued to evolve phonetically, the distinctions among the conjugated forms did not erode (much).
For example, in Latin the words for "I love" and "we love" were, respectively, amō and amāmus. Because a stressed A gave rise to a diphthong in some environments in Old French, that daughter language had (j')aime for the former and (nous) amons for the latter. Though several phonemes have been lost in each case, the different stress patterns helped to preserve distinctions between them, if perhaps at the expense of irregularising the verb. Regularising influences have countered this effect in some cases (the modern French form is nous aimons), but some modern verbs have preserved the irregularity, such as je viens ("I come") versus nous venons ("we come").
Another set of changes already underway by the 1st century CE was the loss of certain final consonants. A graffito at Pompeii reads quisque ama valia, which in Classical Latin would read quisquis amat valeat ("may whoever loves be strong/do well"). In the perfect tense, many languages generalized the -aui ending most frequently found in the first conjugation. This led to an unusual development; phonetically, the ending was treated as the diphthong /au/ rather than containing a semivowel /awi/, and the /w/ sound was in many cases dropped; it did not participate in the sound shift from /w/ to /β̞/. Thus Latin amaui, amauit ("I loved; he/she loved") in many areas became proto-Romance *amai and *amaut, yielding for example Portuguese amei, amou. This suggests that in the spoken language, these changes in conjugation preceded the loss of /w/.
Another major systemic change was to the future tense, remodelled in Vulgar Latin with auxiliary verbs. This may have been due to phonetic merger of intervocalic /b/ and /w/, which caused future tense forms such as amabit to become identical to perfect tense forms such as amauit, introducing unacceptable ambiguity. A new future was originally formed with the auxiliary verb habere, *amare habeo, literally "to love I have". This was contracted into a new future suffix in Western Romance forms which can be seen in the following modern examples of "I will love":
An innovative conditional (distinct from the subjunctive) also developed in the same way (infinitive + conjugated form of habere). The fact that the future and conditional endings were originally independent words is still evident in Portuguese, which in these tenses allows clitic object pronouns to be incorporated as infixes between the root of the verb and its ending: "I will love" (eu) amarei, but "I will love you" amar-te-ei, from amar + te ["you"] + (eu) hei = amar + te + [h]ei = amar-te-ei.
Contrary to the millennia-long continuity of much of the active verb system, which has now survived 6000 years of known evolution, the synthetic passive voice was utterly lost in Romance, being replaced with periphrastic verb forms—composed of the verb "to be" plus a passive participle—or impersonal reflexive forms—composed of a verb and a passivizing pronoun.
Apart from the grammatical and phonetic developments there were many cases of verbs merging as complex subtleties in Latin were reduced to simplified verbs in Romance. A classic example of this is the verbs expressing the concept "to go". Consider three particular verbs in Classical Latin expressing concepts of "going": ire, vadere, and ambulare. In Spanish and Portuguese ire and vadere merged into the verb ir which derives some conjugated forms from ire and some from vadere. andar was maintained as a separate verb derived from ambulare. Italian instead merged vadere and ambulare into the verb andare. And at the extreme French merged all three Latin verbs with, for example, the present tense deriving from vadere and ambulare and the future tense deriving from ire. Similarly the Romance distinction between the Romance verbs for "to be", essere and stare, was lost in French as these merged into the verb être.
The copula (that is, the verb signifying "to be") of Classical Latin was esse. This evolved to *essere in Vulgar Latin by attaching the common infinitive suffix -re to the classical infinitive; this produced Italian essere and French être through Proto-Gallo-Romance *essre and Old French estre as well as Spanish and Portuguese ser (Romanian a fi derives from fieri which means "to become"). However, in Vulgar Latin a second copula developed utilizing the verb stare, which originally meant (and is cognate with) "to stand" to denote a more temporary meaning. That is, *essere signified the essence, while stare signified the state. Stare evolved to Spanish and Portuguese estar and Old French ester (both through *estare), while Italian retained the original form.
The semantic shift that underlies this evolution is more or less as follows: A speaker of Classical Latin might have said (hypothetically, Classical Latin was nearly fully restricted to writing and reserved for rhetorical purposes): vir est in foro, meaning "the man is at the marketplace". The same sentence in Vulgar Latin should have been *(h)omo stat in foru, "the man stands at the marketplace", replacing the est (from esse) with stat (from stare), because "standing" was what was perceived as what the man was actually doing. The use of stare in this case was still actually correct assuming that it meant "to stand", but soon the shift from essere to stare became more wide-spread, and, in the end, essere only denoted natural qualities that would not change. (Although it might be objected that in sentences like Spanish la catedral está en la ciudad, "the church is in the city" this is also unlikely to change, but all locations are expressed through estar in Spanish, as this usage originally conveyed the sense of "the church stands in the city".)
In French, the evolved forms of the two verbs, estre and ester, merged in the late Middle Ages, as the "s" disappeared from words beginning in est-, as this phenomenon produced Modern French être and an obscure form *éter, which eventually merged.
Various books cover the changes between Latin and specific Romance languages, including: