Re: I changed the language in The Sims 4 and my saved games are gone

@EmmaYasmijn  Your user data—saves, saved households and builds, screenshots, etc.—is saved in the Sims 4 user folder in Documents\Electronic Arts.  The Dutch user folder is localized, as in, it's named "De Sims 4" rather than "The Sims 4."  When you switched to English, the game didn't find a "The Sims 4" user folder, so it created a new one with no content.

All you need to do is copy the files from the relevant folders in "De Sims 4" to the ones in "The Sims 4," and your content should appear in-game.  Saves are in the saves folder, saved households and builds are in Tray, screenshots are in Screenshots, etc.