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

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

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 in Italian linguistics "Median Italian", is spoken in the regions of Lazio, Umbria, Central Marche, and in small parts of Abruzzo and Tuscany. It is mainly split across the Roma-Ancona line, which divides the Central dialects into a Northwestern Perimedian group and a Southeastern Median one. Romanesco, the historical dialect of Rome, has lost most of its Central peculiarities and is not a regular part of Central, as it historically is the product of the implantation of Florentine on Old Romanesco, the ancient Median dialect which was spoken in Rome prior to the 1500s.

Neapolitan

The Neapolitan language, or known in Italian linguistics as the "intermediate southern dialect group", is spoken in: southern Marche; southernmost Lazio; Abruzzo; Molise; Campania (including Naples); Basilicata; and the north of both Apulia and Calabria.

Sicilian

In addition, some Gallo-Italic languages are spoken in Central-Southern Italy.

Judeo-Italian

The Judeo-Italian dialects are varieties of Italian used by Jewish communities, between the 10th and the 20th centuries, in Italy and Greece (Corfu and Zakinthos).

Western Romance languages

Based on mutual intelligibility, Dalby lists a dozen languages: Portuguese, Spanish, Asturian-Leonese, Aragonese, Catalan, Gascon, Provençal, Gallo-Wallon, Piedmontese, Ligurian, Lombard, French, Arpitan (or Franco-Provençal), Romansh, and Ladin.

Gallo-Romance

Gallo-Romance includes: Gallo-Romance can include: The Oïl languages, Arpitan, Occitano-Romance and Rhaeto-Romance languages are sometimes called Gallo-Rhaetian.

Iberian-Romance