Some labels are in English in the Polish interface

The interface language is chosen in Settings > General: the system default, Polski or English. In 0.8.1 the labels of the Vault Viewer window (Notes, Graph, Canvas, Reading, Split, Live, Copy path) and of the Repository Index window (Symbols, Files, Routes, Changed, Overview and the other panes) are English also in the Polish interface. This is not a setting you broke.

Nothing to fix on your side. If a label in the main window is in the wrong language, check Settings > General and the language chosen there.