If you need to update the entire game to a different language, you generally cannot do this inside the game menu. You must use your game launcher:
Sims 4 Studio is the primary tool for updating and translating strings. Game guide:Changing the game language | The Sims Wiki sims 4 language strings upd
: Right-click The Sims 4 in your Library, select Properties > General , and choose your language from the dropdown. If you need to update the entire game