Balto-Slavic languages

The Balto-Slavic languages form a branch of the Indo-European family of languages, traditionally comprising the Baltic and Slavic languages. Baltic and Slavic languages share several linguistic traits not found in any other Indo-European branch, which points to a period of common development and origin.

A Proto-Balto-Slavic language is reconstructable by the comparative method, descending from Proto-Indo-European by means of well-defined sound laws, and from which modern Slavic and Baltic languages descended. One particularly innovative dialect separated from the Balto-Slavic dialect continuum and became ancestral to the Proto-Slavic language, from which all Slavic languages descended.

While the notion of a Balto-Slavic unity was previously contested largely due to political controversies, there is now a general consensus among academic specialists in Indo-European linguistics that Baltic and Slavic languages comprise a single branch of the Indo-European language family, with only some minor details of the nature of their relationship remaining in contention.

The nature of the relationship of the Balto-Slavic languages has been the subject of much discussion from the very beginning of historical Indo-European linguistics as a scientific discipline. A few are more intent on explaining the similarities between the two groups not in terms of a linguistically "genetic" relationship, but by language contact and dialectal closeness in the Proto-Indo-European period.

Baltic and Slavic share many close phonological, lexical, morphosyntactic and accentological similarities (listed below). The early Indo-Europeanists Rasmus Rask and August Schleicher (1861) proposed a simple solution: From Proto-Indo-European descended Balto-German-Slavonic language, out of which Proto-Balto-Slavic (later split into Proto-Baltic and Proto-Slavic) and Germanic emerged. Schleicher's proposal was taken up and refined by Karl Brugmann, who listed eight innovations as evidence for a Balto-Slavic branch in the Grundriß der vergleichenden Grammatik der indogermanischen Sprachen ("Outline of the Comparative Grammar of the Indo-Germanic Languages"). The Latvian linguist Jānis Endzelīns thought, however, that any similarities among Baltic and Slavic languages resulted from intensive language contact, i.e. that they were not genetically more closely related and that there was no common Proto-Balto-Slavic language. Antoine Meillet (1905, 1908, 1922, 1925, 1934), a French linguist, in reaction to Brugmann's hypothesis, propounded a view according to which all similarities of Baltic and Slavic occurred accidentally, by independent parallel development, and that there was no Proto-Balto-Slavic language. In turn, the Polish linguist Rozwadowski suggests that the similarities among Baltic and Slavic languages are a result of both a genetic relationship and later language contact. Thomas Olander corroborates the claim of genetic relationship in his research in the field of comparative Balto-Slavic accentology.

Even though some linguists still reject a genetic relationship, most scholars accept that Baltic and Slavic languages experienced a period of common development. This view is also reflected in most modern standard textbooks on Indo-European linguistics. Gray and Atkinson's (2003) application of language-tree divergence analysis supports a genetic relationship between the Baltic and Slavic languages, dating the split of the family to about 1400 BCE.

The traditional division into two distinct sub-branches (i.e. Slavic and Baltic) is mostly upheld by scholars who accept Balto-Slavic as a genetic branch of Indo-European. There is a general consensus that the Baltic languages can be divided into East Baltic (Lithuanian, Latvian) and West Baltic (Old Prussian). The internal diversity of Baltic points at a much greater time-depth for the breakup of the Baltic languages in comparison to the Slavic languages.

"Traditional" Balto-Slavic tree model