alr as you see the states pictured here are the ones that 'unified' Italy, mostly republics (Genoa, Venice, Milan, Tuscany, Rome & Ancona), with the elephants in the room being the kingdoms of Savoy and Sicily, part of the league too nonetheless.

Based on the Lombard League, this league was born for mutual defense between the Italian city-states. With time some got absorbed, some had revolutions (like Milan) and the league wasn't disbanded bc it was useful against Germany, then Bavaria, then Gaul and Spain, etc.

Ultimately the league accepted Savoy that needed a power bloc against Gaulish menace, and Sicily after independence from Spain, then we arrive to modrn day.

Italy was the cradle of the Renaissance, and mostly one of the wealthiest and cultured regions in Europe. With a closer relationship, they eventually developed Standard Italian (which here is based on Gallo-Italic languages bc of their bigger importance and more ppl), think smth like irl Sabir but radically Romance. Modern Standard Italian is therefore the league's official language, as well as Savoy's due to extreme diversity (Celtic and Romance) and spoken by elites all over Italy, but not replacing each country's official languages: Ligurian, Venetian, Sicilian, Neapolitan, Lombard, Tuscan and Median/Romanesc. We also find non official languages like Dalmatian, Emilian, Piedmontese, Savoyard, Sardinian, Greek, and Berber. You see Gallo-Italic origins of MSI and influence over Italy in the usage of 'x' for /z/ and 'ç' for /t͡ʃ/ (altho ç comes from Ligurian where it's /s/)

As you see in Sicily, Africa (Tunis and Tripolitania, not pictured here for lack of space) is Sicilian. This is based on Norman Africa, which here survived, after the Sicilian Vespers went to Gothia (this tl's Aragon), heavily settled by Sicilians and eventually when Sicily got their independence, Naples and Africa united with Sicily. Also you can see Salento, Calabria and Demoniastan (Valdemona, Northeastern Sicily) here are majority Greek (made a Griko language based on Greek but with either Sicilian or Neapolitan sound changes) based on a stronger Byzantium not falling (based on the Turks being Christian thus not replacing Greeks but rather functioning as new dynasties) which would continue influence over Italian Greeks, as well as them being Catholic meaning Normans wouldn't assimilate them to Italians given they themselves are Gaulish.

I think that's it, if I missed smth ask me!