Nouns with the above endings form their plurals according to the following rules:

• Terms in -eise form the plural in -eixi: zeneise “Genoese” > zeneixi.
• Terms in -aise form the plural in -aixi: paise “country” > paixi.
• Terms in -ase and those in -aso form the plural in -axi: ase “donkey” > axi; naso “nose” > naxi.

Generally in Genoese, the letter -s- between vowels is pronounced as a voiced s, -[z]-, in accordance with etymology and with the convention adopted in all Romance languages that have this sound, as in reusa [ˈrøːza] (Italian, Catalan and Portuguese “rosa”, French “rose”), casa [ˈkaːza] (Italian, Catalan and Portuguese “casa”) and sposâ [spuˈzaː] (Italian “sposare”, Catalan “esposar”, French “épouser”).

For certain words, mainly due to the historical lack of a definitive standard for written Genoese, conflicting spellings have spread and still coexist in which this sound is represented with -z-, such as zeneize [zeˈnejze] “Genoese”, creuza [ˈkrøːza] “narrow alley between two walls”, and cazann-a/cazaña [kaˈzaŋˑa] “customer”.

In this dictionary, in line with the rules of written Genoese adopted in many other contexts, these terms are written according to the parameters of the general rule stated above (i.e. zeneise, creusa, casaña). Indeed, spellings such as zeneize would also legitimise eccentric forms like caza [ˈkaːza] “house” or nazo [ˈnaːzu] “nose”, which must instead be written casa, naso.

Before a long vowel marked with a diaeresis, however, -s- is pronounced voiceless, -[s]-, as in the Italian sole: cäsiggion [kaːsiˈdʒuŋ] “mushroom stem”, cösa [ˈkɔːsa] “thing”, fäso [ˈfaːsu] “false”, pösâ [pɔˈsaː] “to put down”.

The only cases requiring the spelling -z- are once again dictated by etymology: mezo [ˈmeːzu] “half, middle” < medju(m), caize [ˈkajze] “soot” < *calige(m), strazzetto [straˈzetˑu] “suburban lane” < ex trajectu(m).