It is useful to understand that although from 1940 to 1991 Latvia was a part of the USSR, the official language is Latvian. However, a significant minority (up to 30% nationwide and possibly about 45% in the capital Riga) is Russian. The majority of ethnic Latvians living in the city, especially those old enough to have attended school during Soviet times, can also speak and understand Russian. Latvian and Russian belong to different language groups and the difference between them is about as large as difference between English and French. English and also German are widely understood at places regularly visited by tourists and foreigners but you may be out of luck when leaving the city center or visiting places off the beaten track, where you get by only in Latvian or Russian. Young people (born in 1975 or later) usually can speak English anyway. http://wikitravel.org/en/Riga