Italo-Western is, in some classifications, the largest branch of the Romance languages. It comprises two of the branches of Romance languages: Italo-Dalmatian and Western Romance. It excludes the Sardinian language and Eastern Romance. Italo-Dalmatian languages Based on the criterion of mutual intelligibility, Dalby lists four languages: Italian (Tuscan), Corsican, Neapolitan–Sicilian-Central Italian, and Dalmatian. Dalmatian Romance The Dalmatian language was spoken in the Dalmatia region of Croatia. It became extinct in the 19th century. The Istriot language is a moribund variety spoken in the southwestern part of Istrian peninsula in Croatia. Venetian The Venetian language is sometimes added to Italo-Dalmatian when excluded from Gallo-Italic, and then usually grouped with Istriot. However, Venetian is not grouped into the Italo-Dalmatian languages by Ethnologue and Glottolog, unlike Istriot. Tuscan Tuscan-Corsican: group of dialects spoken in the Italian region of Tuscany, and the French island of Corsica. Northern Tuscan dialects: Florentine is spoken in the city of Florence, and was the basis for Standard Italian. Other dialects: Pistoiese; Pesciatino or Valdinievolese; Lucchese; Versiliese; Viareggino; Pisano-Livornese. Southern Tuscan dialects: Dialects of Aretino-Chianaiolo, Senese, Grossetano. Corsican, spoken on Corsica, is thought to be descended from Tuscan. Gallurese and Sassarese, spoken on the northern tip of Sardinia, can be considered either dialects of Corsican or Corso-Sardinian transitional varieties. Italian Italian is an official language in Italy, Switzerland, San Marino, Vatican City and western Istria (in Slovenia and Croatia). It used to have official status in Albania, Malta and Monaco, where it is still widely spoken, as well as in former Italian East Africa and Italian North Africa regions where it plays a significant role in various sectors. Italian is also spoken by large expatriate communities in the Americas and Australia. The Italian language was initially and primarily based on Florentine: it has been then deeply influenced by almost all regional languages of Italy while its received pronunciation (known as Pronuncia Fiorentina Emendata, Amended Florentine Pronunciation) is based on the accent of the Roman dialect; these are the reasons why Italian differs significantly from Tuscan and its Florentine variety. Central Italian Central Italian, or Latin-Umbrian-Marchegian and in Italian linguistics as "middle Italian dialects", is mainly spoken in the regions of: Lazio (which includes Rome); Umbria; central Marche; a small part of Abruzzo and Tuscany. Romanesco, spoken in Rome, Lazio. As mentioned above, it is the basis of the accent of the received pronunciation in standard Italian. Tuscia or Viterbo: