BLS branches and divisions operate in 76 Belarusian towns and villages as well as in Moscow, Irkuck, Vilnia, St. Petersburg and Riga.
Constitutional Provisions of the Eastern Partnership Member States and Kazakhstan concerning the State Language and other Languages. A Comparative Survey.
As UNESCO web site has it, International Human Rights Law plays an important role in setting standards for linguistic rights and, especially, for the protection and promotion of the identity of linguistic minority groups. It provides the normative framework for developing principles of democratic governance and multicultural policies aimed at managing ethno-linguistic conflict.
Here is a short sample list of UN rulings that include dispositions or deal directly with language issues and the rights of their speakers. The list is borrowed from http://www.ciemen.org/mercator/onu-gb.htm.