Balto-Slavic

adjective2

1. •
   Of or pertaining to both the Baltic and Slavic language families, which together constitute a branch or dialect group within the larger Indo-European family.

   • Of the modern Balto-Slavic languages, Lithuanian is often regarded as the most conservative in morphology and phonology, followed closely by Latvian.
2. •
   Of or pertaining to the (Proto-)Balto-Slavic language, the people who spoke it, or their culture.