Latgalian language
Originally Latgalians were a tribe living in modern Vidzeme and Latgale. It is thought that they spoke the Latvian language, which later spread through the rest of modern Latvia, absorbing features of the Old Curonian, Semigallian, Selonian and Livonian languages. The Latgale area became politically separated during the Polish–Swedish wars, remaining part of the Polish–Lithuanian Commonwealth as the Inflanty Voivodeship, while the rest of Latvians lived in lands dominated by Baltic German nobility. Both centuries of separate development and the influence of different prestige languages likely contributed to the development of modern Latgalian as distinct from the language spoken in Vidzeme and other parts of Latvia.
Livonians
The Livonians, or Livs (Livonian: "līvlizt"), are a Finnic ethnic group indigenous to northern Latvia and southwestern Estonia. Livonians historically spoke Livonian, a Uralic language closely related to Estonian and Finnish. The last person to have learned and spoken Livonian as a mother tongue, Grizelda Kristiņa, died in 2013, making Livonian extinct. As of 2010, there were approximately 30 people who had learned it as a second language.