Language option doesnt work

I am experiencing an issue with the Estatik plugin settings. I am trying to change the plugin language to Russian, Latvian, or another language using the Language setting in Estatik > Settings > General, but nothing changes—the front end of the plugin remains in English. I also cleared the cache, but it still doesn’t work.

Is the language option in the plugin currently not functioning or what?
Also, is there a way to change the language manually?