an independent branch of the Indo-European language family. Modern Latvian (spoken by most of the population of the Latvian SSR) and Lithuanian (spoken by most of the population of the Lithuanian SSR), as well as the extinct Old Prussian language (spoken by the indigenous population of Eastern Prussia, already obliterated or artificially Germanized by the end of the 17th century), belong to the Baltic group of languages. Unwritten Baltic languages, mentioned in Russian chronicles, also existed: the languages of the Iatviagi, Goliad’, and Kurŝiai (Kurs or Kurony—Curonian). The origin of the Baltic languages and their relationship to the Slavic languages, with which they share many common lexical and grammatical features, represents a complex problem.
The Baltic languages were first studied by the German scholars A. Schleicher, A. Leskien, and J. Nesselmann. Later, much work was done by the Russian scholars F. F. Fortunatov, G. K. Ul’ianov, and V. K. Porzhezinskii; the Lithuanian scholars F. Kurŝat and K. Büga; the Latvian scholar J. Endzelīns; and the German scholars F. Specht, E. Fraenkel, and others. The work of those who gathered folklore (the Latvian K. Barons and others) and literary figures (the Lithuanian J. Jablonskis and others) was of great importance for the study of the Baltic languages. Dialect materials were collected in the late 19th century by A. Baranovskii, A. Bilenstein, K. Javnis, and others.