Latvian language
Upper Latvian dialect is spoken in Eastern Latvia. It is set apart from rest of the Latvian by number of phonetic differences. The dialect has two main varieties – Selonian and Non-Selonian. There is a standard language, the Latgalian language, which is based on deep Non-Selonian varieties spoken in south of Latgale. The term "Latgalian" is sometimes also applied to all Non-Selonian varieties or even the whole dialect. However, it is unclear if it is accurate to use the term for any varieties besides the standard language. While the term may refer to varieties spoken in Latgale or by Latgalians, not all speakers identify as speaking Latgalian, for example, speakers of deep Non-Selonian varieties in Vidzeme explicitly deny speaking Latgalian.
Russian language in Latvia
In the 1925 census Russians were already reported as the largest minority (10.6%) and Russian was spoken as the family language by 14% of inhabitants. A small percent of Russian speakers were not ethnic Russians and conversely a small percentage of ethnic Russians used another language in family, which was attributed to mixed marriages, living in area with another majority language and, in case of Russian speakers, Russification policies of Russian empire. In 1930 census Russian was reported as family language by 13% of inhabitants.