ProtoBaltoSlavic

ProtoBaltoSlavic, or Proto-Balto-Slavic, is the reconstructed common ancestor of the Baltic and Slavic language families. It is not directly attested but is inferred from regular phonological, morphological, and lexical correspondences among Baltic languages (for example Lithuanian and Latvian) and Slavic languages (for example Russian and Polish).

Reconstruction of PBS rests on the comparative method. The hypothesis posits a single protorlanguage that split into Baltic and Slavic branches after the wider Indo-European fragmentation. Evidence includes systematic sound correspondences, shared inflectional patterns, and a core vocabulary with cognates across both groups.

Dating and geography: Most scholars place the divergence in the late Bronze Age or early Iron Age, roughly between the 2nd and 1st millennium BCE, with the homeland near the eastern Baltic coast and adjacent eastern Europe. This timing aligns with archaeological and historical indicators of population movements in the region.

Features: PBS is imagined to preserve a highly inflected, fusional grammar with noun cases and possibly dual number, along with a basic Indo-European lexicon. Shared changes versus the branches reflect both retention of archaisms and early developments that may have occurred in one or both lineages after their split.

Status: The concept of Proto-Balto-Slavic is widely used but debated. Some linguists regard PBS as a valid reconstructable stage, while others emphasize substantial later contact or parallel development. Nevertheless, the hypothesis provides a framework for studying the deeper history of Baltic and Slavic languages within Indo-European.