The Switch version of L.A. Noire (released in 2017) follows standard console protocols.
If the game was purchased directly from Rockstar or if the Steam version launches through the Rockstar Launcher: la noire how to change language
If you switch languages and characters suddenly have no voices (just subtitles), you haven't downloaded the full voice pack. Go back to Steam/Rockstar Launcher and ensure the language download completed. The audio folders should total roughly 13 GB. The Switch version of L