Italian dialects are separate languages geographically distributed throughout the peninsula, which differ from each other to the extent of being mutually unintelligible if they belong to non-adjacent areas. The reason for such profound diversity is to be found initially in a different evolution of spoken Latin in the various parts of Italy during the Middle Ages, and in the following centuries of political fragmentation before final unification in 1861. In relation to the Italian language-the national language-today the dialects are ‘low languages’ in the sense that they are used mainly orally in a narrower geographical area (dialect usage). Although they are still very vital, in the last decades they have been undergoing a process of Italianization as a result of their intense contact with Italian and the latter’s increasing use nationwide. Consequently, dialects are tending to become more uniform throughout their region or province as they are losing their more local features. At the same time, they also influence the way Italian is used in the various regions, particularly at the level of pronunciation and vocabulary (see varieties of Italian).