What is localization and why is it important?

I’ve been seeing this term around, and after some research I still don’t understand what it is or why it’s important.

Can I get a “ELI5” write-up?

Localization is translating the user-interface portion of your game to other languages.

Is that all it’s used for? I did gather that from googling… But I didn’t think that was all.

well, localization and internationalization are different things.

And yeah, google could clear a lot, search for those 2 terms, at less on wikipedia.