Proto-Romance is the result of applying thecomparative method toreconstruct the latest common ancestor of theRomance languages. To what extent, if any, such a reconstruction reflects a realétat de langue is controversial. The closest real-life counterpart would have been a late variety ofLatin.

/au̯/ appears to be the only phonemic diphthong that can be reconstructed.^[1]

• Vowels were lengthened in stressed open syllables.^[2]
• Stressed/ɛɔ/ may have yielded incipientdiphthongs like[e͡ɛo͡ɔ] inmetaphonic conditions.^[3][i]
  • Metaphony, if it can be projected back to Proto-Romance, may have initially been limited to open syllables. That is, it would have targeted allophonically lengthened/ɛɔ/.^[4]

• /ɛɔ/ did not occur in unstressed position.^[5]
• /iu/ did not occur in the second syllable of words with the structureˌσσˈσσ.^[6][ii]

• There is scholarly disagreement over whether palatalization was phonemic in Proto-Romance.^[7][iii]
• Palatalized consonants tended togeminate between vowels. The extent of this varied by consonant.^[8][iv]
• /tʲ/ would have been anaffricate like[t͡sʲ]^[9] or[t͡zʲ].^[10]

• /sC/ in word-initial position was assigned aprop-vowel [ɪ], as in/ˈstare/[ɪsˈtaːɾe].^[11][v]
• /ɡn/ was likely[ɣn] at first, with later developments varying by region.^[12][vi]
• /dɡ/ might have been fricatives or approximants between vowels.^[13]
• /ll/ might have beenretroflex.^[14][vii]
• /f/ might have beenbilabial.^[15]

• /b/ did not occur in intervocalic position.^[16][viii]

The forms below are spelt as they are in the cited sources, either in Latin style or in phonetic notation. The latter may not always agree with the phonology given above.

Nouns are reconstructed as having three cases: anominative, anaccusative, and agenitive-dative:^[17][ix]

Some nouns of the –C type had inflections with alternating stress or syllable count:^[18]

There were also ‘neuter’ nouns. In the singular they would have been treated as masculine and in the plural as feminine, often with a collective sense.^[19]

For the most part, the typical way to form a comparative would have been to addmagis orplus (‘more’) to a positive adjective. A few words can be reconstructed as having a comparative ending-ior, which would have been inflected as follows:^[20]

Superlatives would have been formed by adding definite articles to comparatives.^[21]

The stressed or 'strong' forms:^[22]

The unstressed or 'weak' forms:^[23]

As follows:^[24]

• Phonological changes from Classical Latin to Proto-Romance

• Adams, James Noel (2013).Social variation and the Latin language. Cambridge University Press.doi:10.1017/CBO9780511843433.ISBN 978-0-511-84343-3.
• Alkire, Ti; Rosen, Carol (2010).Romance languages: A historical introduction. Cambridge University Press.ISBN 978-0-521-88915-5.
• Barbato, Marcello (2022)."The early history of Romance palatalizations".Oxford Research Encyclopedias.doi:10.1093/acrefore/9780199384655.013.750.ISBN 978-0-19-938465-5.
• Burger, André (1955). "Phonématique et diachronie à propos de la palatalisation des consonnes romanes".Cahiers Ferdinand de Saussure.13 (13):19–33.JSTOR 27757997.
• Chambon, Jean-Pierre (2013). "Notes sur un problème de la reconstruction phonétique et phonologique du protoroman: Le groupe */ɡn/".Bulletin de la Société de Linguistique de Paris.CVIII (1):273–282.doi:10.2143/BSL.108.1.3019219.
• de Dardel, Robert & Gaeng, Paul Ami (1992). "La declinaison nominale du latin non classique: Essai d'une methode de synthese".Probus.4 (2):91–125.doi:10.1515/prbs.1992.4.2.91.
• de Dardel, Robert & Wüest, Jakob (1993). "Les systèmes casuels du protoroman: Les deux cycles de simplification".Vox Romanica (52):25–65.
• Dworkin, Steven N. (2016). "Do romanists need to reconstruct Proto-Romance? The case of the Dictionnaire Étymologique Roman project".Zeitschrift für romanische Philologie (132):1–19.doi:10.1515/zrp-2016-0001.
• Elcock, William Dennis (1960).The Romance languages. London: Faber and Faber.
• Ferguson, Thaddeus (1976).A history of the Romance vowel systems through paradigmatic reconstruction. Berlin: De Gruyter.doi:10.1515/9783110806960.ISBN 978-3-11-080696-0.
• Gouvert, Xavier (2015). "Le système phonologique du protoroman: essai de reconstruction". In Buchi, Éva; Schweickard, Wolfgang (eds.).Dictionnaire Étymologique Roman. Berlin: De Gruyter. pp. 61–128.doi:10.1515/9783110313482.ISBN 978-3-11-031244-7.
• Gouvert, Xavier (2016). "Du protoitalique au protoroman: deux problèmes de reconstruction phonologique". In Buchi, Éva & Schweickard, Wolfgang (eds.).Dictionnaire Étymologique Roman 2. Berlin: De Gruyter. pp. 27–51.doi:10.1515/9783110453614.ISBN 978-3-11-045361-4.
• Grandgent, Charles Hall (1907).An introduction to Vulgar Latin. Boston: D.C. Heath & Co.
• Hall, Robert Anderson (1976).Proto-Romance phonology. New York: Elsevier.ISBN 978-0-444-00183-2.
• Hall, Robert Anderson (1983).Proto-Romance morphology. Philadelphia: John Benjamins.ISBN 978-90-272-3522-0.
• Lausberg, Heinrich (1970) [1965].Lingüística románica. Vol. I–II. Translated by Pérez Riesco, José; Pascual Rodríguez, E. (2nd ed.). Madrid: Gredos.
  • Original in German:Romanische Sprachwissenshaft. Berlin: De Gruyter. 1956–62.
• Loporcaro, Michele (2015).Vowel length from Latin to Romance. Oxford University Press.doi:10.1093/acprof:oso/9780199656554.003.0001.
• Lloyd, Paul Max (1987).From Latin to Spanish: Historical phonology and morphology of the Spanish language. Philadelphia: American Philosophical Society.ISBN 978-0-87169-173-6.
• Lyons, Christopher (1986). "On the origin of the Old French strong-weak possessive distinction".Transactions of the Philological Society.84 (1):1–41.doi:10.1111/j.1467-968X.1986.tb01046.x.
• Maiden, Martin (2016). "Diphthongization". In Ledgeway, Adam; Maiden, Martin (eds.).The Oxford guide to the Romance languages. Oxford University Press. pp. 647–57.doi:10.1093/acprof:oso/9780199677108.001.0001.ISBN 978-0-19-967710-8.
• Operstein, Natalie (2010).Consonant structure and prevocalization. Current Issues in Linguistic Theory. Vol. 312. Amsterdam: John Benjamins.doi:10.1075/cilt.312.ISBN 978-90-272-4828-2.
• Petrovici, Emil (1956). "Problema moştenirii din romanica comună a corelaţiei palatale a consoanelor în limba romînă".Ştudii şi Cercetări Lingvistice.7:163–9.
• Pope, Mildred Katherine (1952) [1934].From Latin to Modern French (2nd ed.). Manchester University Press.
• Repetti, Lori (2016). "Palatalization". In Ledgeway, Adam; Maiden, Martin (eds.).The Oxford guide to the Romance languages. Oxford University Press. pp. 658–68.doi:10.1093/acprof:oso/9780199677108.001.0001.ISBN 978-0-19-967710-8.
• van den Bussche, Henri (1985). "Proto-Romance inflectional morphology. Review ofProto-Romance morphology by Robert Hall".Lingua.66 (2–3):225–60.doi:10.1016/S0024-3841(85)90336-5.
• Zampaulo, André (2019).Palatal sound change in the Romance languages: Diachronic and synchronic perspectives. Oxford University Press.doi:10.1093/oso/9780198807384.001.0001.ISBN 978-0-19-880738-4.

• Forms of Latin
• Romance languages
• Proto-languages

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• Articles containing French-language text
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