This mod changes your GAME LANGUAGE. Yes, it does. Since Origin turned into EA App it has been removed the 'Change Language' options. Now, if you want your game language you will have to UNISTALL & REINSTALL your game each time.

With this mod you will just have to install a file in your Mods folder and the trick is done. Voilà, today I want to play in Italian and tomorrow in English, NOW I CAN! I know that my multilingual friends who miss to play in their native language, or just want to experiment a second language, are there wondering if it's the case to re-install 50+GB of a game to change a language. Now, just have fun!
PLEASE READ THE SECTION BELOW OF IMPORTANT NOTES. THERE ARE SOME THINGS I'M NOT THAT GENIUS ABOUT THAT I COULDN'T CHANGE.

IMPORTANT NOTES

There are some things you must keep in mind before changing the language.

1) Lots. If you will play on an existent save, Lots name won't be changed. If your game is in Italian and you change to English, you will still have Italian lots name on an existent save. On a new save, it will be consistent and they will be in English.

2) Sim's names. They will still be randomized based on your original game language, but you can use mods like Townie Demographic by Kuttoe to give some consistency to the game. Sorry, I couldn't do nothing about it (maybe in the future).

3) Pronouns. If you are looking to use the pronouns feature (available only for the English game), by installing the English version of this mod, it won't work. I can suggest you to re-install your game in English and then use one of my Translations here to play in your native language. Speaking of pronouns, if your game is in English and you change the language with this mod you will still have the pronouns feature, but it won't work. And it will still be written in English. I could've change that, translate it in any language, but it's useless. You can't use it anyway.

4) Calendar & time. Calendar names and times won't change. For example, if you have the English game and install the Spanish version, on the calendar it will still be displayed Sunday, Monday, Tuesday etc. and the time will still be 12Hours. I'm sorry, I know it sucks, but I could not do anything for that. But I promise the rest is completely translated!!!!!!!!

5) Screenshots & Video folders. In your The Sims 4 folder, as you all know, you have the Screenshots & Video folder where it get stored all the pics and video taken directly in game with the game's feature. If you install a new version, you will have new folder. Let me make it clear: if your game is in English, you have the Screenshots & Recorded Videos folders. Once you open the game with the translation in, it will create the same two folders in the language of the mod installed. So, if you install Italian you will have Immagini for Screenshots and Video Registrati for RecordedVideos. Every pic and video taken in the game with the translation in will go in the Italian (in that example) folder. You take the translation out and it will go in the English folders again.

6) Mods language. Mods that include translations will match your original game language, and translations won't work. To know how to make everything works, I've wrote THIS TUTORIAL for you. It's easy and peasy, so you can do it by yourself, but you can find a way to conctact me anyway if you ever need help.

7) The ADS on the main page. The ADS on your main page will be in the language of your EA App. I can't change it for you, you can only do it by reinstalling the EA App (only the app, NOT THE GAME) to the language you choose to make it match. But honestly it's just like 3 squares that is not even worth it.

Multilingual Distress: Language Changer