In Switzerland, Italian is one of four official languages, spoken mainly in the Swiss cantons of Grigioni and Ticino. It is also the official language of San Marino, as well as the primary language of Vatican City.
It is co-official in Slovenian Istria and in part of the Istria County in Croatia. The Italian language adopted by the state after the unification of Italy is based on the Tuscan dialect, which beforehand was only available to upper class Florentine society.
Its development was also influenced by other Italian dialects and by the Germanic language of the post-Roman invaders.
Italian derives diachronically from Latin and is the closest national language to Latin. Unlike most other Romance languages, Italian retains Latin's contrast between short and long consonants. As in most Romance languages, stress is distinctive.
In particular, among the Romance languages, Italian is the closest to Latin in terms of vocabulary. Lexical similarity is 89% with French, 87% with Sardinian, 85% with Catalan, 82% with Spanish, 78% with Rhaeto-Romance and 77% with Romanian.