Baltic languages, a subfamily of the Indo-European family of languages. The Indo-European subfamily to which the Baltic languages appear to be closest is the Slavic. Because of this, some linguists regard Baltic and Slavic as branches of a single Balto-Slavic division of the Indo-European family. The Baltic tongues are thus named because they are spoken in an area bordering on the Baltic Sea. The principal ones are Latvian (or Lettish) and Lithuanian (together native to about 6.5 million people in Eastern Europe) and Old Prussian (which ceased to be a living language during the 17th cent.). The early common ancestor of the various Baltic languages, both living and dead, is traditionally referred to as Proto-Baltic. It is thought that Proto-Baltic broke off from the other Indo-European languages before 1000 B.C. A further division into East Baltic (to which Latvian and Lithuanian belong) and West Baltic (which claims Old Prussian) is believed to have taken place before 300 B.C. The Baltic languages are said to be the closest of the living Indo-European languages to Proto-Indo-European—the original parent of all the Indo-European tongues—both phonologically and grammatically. They show a high degree of inflection in both the noun and verb systems. The earliest surviving text in a Baltic language may be dated c.1400, but by the 16th cent. documents had become fairly numerous. See also Latvian, Lithuanian, Indo-European.
See T. F. Magner and W. R. Schmalstieg, ed., Baltic Linguistics (1970).