Editing Romance languages (section)

==== Latin diphthongs ====
The Latin diphthongs {{lang|la|ae}} and {{lang|la|oe}}, pronounced {{IPA|/aj/}} and {{IPA|/oj/}} in earlier Latin, were early on monophthongized.{{sfn|Clackson|2016|page=6}}

{{lang|la|ae}} became {{IPA|/ɛː/}} by{{Citation needed|date=March 2024}} the 1st century {{smallcaps|a.d.}} at the latest. Although this sound was still distinct from all existing vowels, the neutralization of Latin vowel length eventually caused its merger with {{IPA|/ɛ/}} < short ''e'': e.g. ''caelum'' "sky" > French {{lang|fr|ciel}}, Spanish/Italian {{lang|es|cielo}}, Portuguese {{lang|pt|céu}} {{IPA|/sɛw/}}, with the same vowel as in ''mele'' "honey" > French/Spanish {{lang|fr|miel}}, Italian {{lang|it|miele}}, Portuguese {{lang|pt|mel}} {{IPA|/mɛl/}}. Some words show an early merger of ''ae'' with {{IPA|/eː/}}, as in ''praeda'' "booty" > *''prēda'' {{IPA|/preːda/}} > French {{lang|fr|proie}} (vs. expected **''priée''), Italian {{lang|it|preda}} (not **''prieda'') "prey"; or ''faenum'' "hay" > *''fēnum'' {{IPA|[feːnũ]}} > Spanish {{lang|es|heno}}, French {{lang|fr|foin}} (but Italian {{lang|it|fieno}} /fjɛno/).

{{lang|la|oe}} generally merged with {{IPA|/eː/}}: ''poenam'' "punishment" > Romance *{{IPA|/pena/}} > Spanish/Italian {{lang|es|pena}}, French {{lang|fr|peine}}; ''foedus'' "ugly" > Romance *{{IPA|/fedo/}} > Spanish {{lang|es|feo}}, Portuguese {{lang|pt|feio}}. There are relatively few such outcomes, since {{lang|la|oe}} was rare in Classical Latin (most original instances had become Classical {{lang|la|ū}}, as in Old Latin {{lang|la|oinos}} "one" > Classical {{lang|la|ūnus}}<ref name="Palmer">Palmer (1954).</ref>) and so {{lang|la|oe}} was mostly limited to Greek loanwords, which were typically learned (high-register) terms.

''au'' merged with ''ō'' {{IPA|/oː/}} in the popular speech of Rome already by the 1st century {{smallcaps|b.c}}.{{Citation needed|date=November 2023|reason=Quite bold to claim that the entire phoneme /aw/ was lost to such a merger in the first century BC, in light of the modern Roman dialect reflecting no such thing (rather showing outcomes similar to those of Tuscan/Standard Italian).}} A number of authors remarked on this explicitly, e.g. [[Cicero]]'s taunt that the populist politician [[Publius Clodius Pulcher]] had changed his name from ''Claudius'' to ingratiate himself with the masses. This change never penetrated far from Rome, however, and the pronunciation /au/ was maintained for centuries in the vast majority of Latin-speaking areas, although it eventually developed into some variety of ''o'' in many languages. For example, Italian and French have {{IPA|/ɔ/}} as the usual reflex, but this post-dates diphthongization of {{IPA|/ɔ/}} and the French-specific palatalization {{IPA|/ka/}} > {{IPA|/tʃa/}} (hence ''causa'' > French {{lang|fr|chose}}, Italian {{lang|it|cosa}} {{IPA|/kɔza/}} not **''cuosa''). Spanish has {{IPA|/o/}}, but Portuguese spelling maintains {{angbr|ou}}, which has developed to {{IPA|/o/}} (and still remains as {{IPA|/ou/}} in some dialects, and {{IPA|/oi/}} in others).{{sfn|Boyd-Bowman|1980|pp=24–25}} Occitan, Dalmatian, Sardinian, and many other minority Romance languages still have {{IPA|/au/}} while in Romanian it underwent diaresis like in {{lang|la|aurum}} > {{lang|ro|aur}} (a-ur).{{Sfn|Sala|2012|p=145}} A few common words, however, show an early merger with ''ō'' {{IPA|/oː/}}, evidently reflecting a generalization of the popular Roman pronunciation:{{Citation needed|date=March 2024}} e.g. French {{lang|fr|queue}}, Italian {{lang|it|coda}} {{IPA|/koda/}}, Occitan {{lang|oc|co(d)a}}, Romanian {{lang|ro|coadă}} (all meaning "tail") must all derive from ''cōda'' rather than Classical ''cauda''.<ref>''cauda'' would produce French **{{lang|fr|choue}}, Italian {{IPA|*/kɔda/}}, Occitan **{{lang|oc|cauda}}, Romanian **{{lang|ro|caudă}}.</ref> Similarly, Spanish {{lang|es|oreja}}, Portuguese {{lang|pt|orelha}}, French {{lang|fr|oreille}}, Romanian {{lang|ro|ureche}}, and Sardinian {{lang|sc|olícra}}, ''orícla'' "ear" must derive from ''ōric(u)la'' rather than Classical ''auris'' (Occitan {{lang|oc|aurelha}} was probably influenced by the unrelated ''ausir'' < ''audīre'' "to hear"), and the form ''oricla'' is in fact reflected in the [[Appendix Probi]].