Names for Latvians by different nations
Hello! I'm writing a non-fiction book, where one of my characters, Alexander, goes to travel across Europe and eventually ends up in Latia. I've been trying to research more into local languages, customs, traditions, etc. of the different countries Alex is visiting so I can include them in the story. What peaked my interest are the local slang and unique words/names in each country. I don't speak Latvian though so I can't really find anything nor check if that's true or not.
I sometimes see and hear news sources and various peoples in general refer to Latvians as "Livonians"/"Livs" or "Latgalians", even though both of these names seem to be for distinct different ethnicities? I also tried searching for synonyms and different names of Latvians, but so far no results. Russian man from Latvia once told me they call Latvians usratyshy (maybe derived from Russian word for Latvians?).