Metaphony in the southern Italian languages is triggered by final and. High-mid vowels are raised to, and low-mid vowels are either raised to or diphthongized to. Metaphony is not triggered by final. The main occurrences of final are as follows:
Masculine "mass" nouns, and "neuter" demonstratives.
The main occurrence of final is in masculine "count" nouns. Metaphony in the northern Italian languages is triggered only by final. In these languages, as in Tuscan, final was lowered to ; it evidently happened prior to the action of metaphony. In these languages, metaphony also tends to apply to final, raising it to or. In most Italian languages, most final vowels have become obscured or lost, and the effects of metaphony are often the only markers of masculine vs. feminine and singular vs. plural.
In some of the Astur-Leonese dialects, in northern Spain, a distinction between mass and count nouns appeared at an early stage. Count nouns from Latin masculines preserved the -u from Latin accusative, while mass nouns from Latin masculines were marked by an, this is traditionally referred to as ″mass-neuter″. In addition, Astur-Leonese marked masculine plurals with . In this situation, only masculine singular count nouns developed metaphony, as they were the ones marked with a, and mass nouns and plurals, marked with, did not. This ending system has been preserved in only central Asturian dialects. Unlike metaphony, which is considered dialectal, it has also been included in the standard version of Asturian. However, at later stages, Eastern Astur-Leonese dialects lost the u/o distinction in noun gender markers. Some of those dialects also lost metaphony and the noun count/mass distinction altogether, keeping it only in their pronoun systems, others, such as Pasiegu from Eastern Cantabria closed all their mid-vowels in word ending syllables, and relied on metaphony as a means for distinguishing mass/count nouns. Some Astur-Leonese dialects also presented i-triggered metaphony. It is also considered dialectal, and it is most prevalent in imperatives, preterites and demonstratives. Sometimes it prevents diphthongation by closing the mid vowel in the verbal stem.
Portuguese
Raising of to by a following final occurs sporadically in Portuguese. Example: porcum, porcōs "pig, pigs" > PIR > Portuguese porco vs. porcos ; novum, novōs, novam, novās "new " > PIR > Portuguese novo vs. novos, nova, novas. In this case, Old Portuguese apparently had in the singular vs. /os/ in the plural, despite the spelling ⟨-o -os⟩; a later development has raised plural to. Unlike elsewhere, this development is only sporadic and only affects, not. Furthermore, the mass/count distinction is expressed very differently: Only a few "mass neuter" demonstratives exist, and they have a higher rather than lower vowel ", isto "this " vs. este "this. In addition, the original pattern has been extended to some nouns originally in.
Romanian
shows metaphony of the opposite sort, where final caused a diphthongization >, >, > : cēram "wax" > ceară; equam "mare" > > > iapă; flōrem "flower" > floare; nostrum, nostrī, nostram, nostrās "our " > > nostru, noștri, noastră, noastre.
Sardinian
likewise has a distinction between final and , along with metaphony. In the conservative Logudorese and Nuorese dialects, the result of metaphony is a non-phonemic alternation between and . In Campidanese, final have been raised to, with the result that the metaphonic alternations have been phonemicized.
