Russia is to raise concerns about the rights of hundreds of thousands of Russian-speakers in Latvia and Estonia.
The language law prompted protests from Russian students
Russian officials will make their case at talks with the Organisation for Security and Co-operation in Europe.
A foreign ministry spokesman said Latvia's plan for secondary education to be conducted predominantly in Latvian required thorough examination.
He said Russia would also raise the position of ethnic minorities in other former Soviet republics.
The OSCE is the largest regional security organisation in the world with 55 participating states from Europe, central Asia and North America.
It is involved in conflict prevention, crisis management and post-conflict rehabilitation.
Moscow is particularly concerned with Latvia's plans to limit the language, educational and other rights of Russian-speakers.
A law reducing the use of Russian in education was passed last month, prompting angry protests by thousands of ethnic Russian students.
The Latvian government says the bill is meant to help integrate minorities.
The former Soviet republic is due to join the European Union in May after a decade of readjustment and reforms.
Russian foreign ministry spokesman Alexander Yakovenko said: "Russia's concern is based on the estimates of the actual state of affairs in this respect by the Russian-speaking residents of Latvia and Estonia, and by many authoritative international and non-governmental human rights organisations."
He said the outflow of Russians from former Soviet states and Central Asia was caused "not only by economic difficulties but also by the deliberate ousting of the Russian language in some countries in the region from social, political and cultural life and that of Russian-speakers from the market of labour".
Russia's talks with the OSCE are taking place in Moscow on Wednesday and Thursday.