The dominating language in the USSR was Russian, and it was heavily promoted in schools and public life at the expense of local languages.
Document data: 24.06.2020. Link: https://euvsdisinfo.eu/being-occupied-as-a-privilege_baltic_states/
Publisher’s notes: as the data from Latvia itself show, Latvian was dominating in Latvia’s schools at the end of Soviet rule. Languages of smallers minorities like Belarusian and Polish were restricted during the Soviet rule, indeed, – but not just in favour of Russian. Parents could also send their children to schools with instruction in Latvian. For some documents on education from Soviet Latvia, see in the Imagery section.