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.
Latvian grammar
Unlike, for example, Romance languages where conjugation classes are assigned based on thematic vowels (e.g., "-are", "-ere", "-ire" forming, respectively, the 1st, 2nd and 3rd conjugation in Italian) Latvian verbs are classified in conjugations regardless of whether they end in "-āt", "-ēt", "-īt", "-ot" or "-t". The classification depends on whether the verb stem has a thematic vowel, and if so, whether it is retained in present tense.