Can't edit RldOrigin (language) after Fitness Stuff [SOLVED]

Hi! I've just downloaded the Fitness Stuff and I wanted to change the language (I'm Czech and my sister refuses to play it in English, unfortunately), but when I tried to change the es_US, it said that I can't edit this file and I should create a new one. When I tried to make it, it hasn't changed anything. Don't you know what to do with that? 

And for all of you who also has an end of the school year today, have great holidays.
M.

Rightclick on the folder Bin.
Select Properties
Uncheck the read-only box
Click Apply
Click OK

Now change the file RldOrigin.ini and save it
After changing a language always start the game as an administrator.

Should you wish to play in 2 different languages, you in English, your sister in Chech, Copy the complete install folder The Sims 4 to a different location on your computer.
Make a new shortcut from either TS4.exe or TS4_x64.exe of that new location on your desktop.
Set to the required language and now you can both play your own game without interfering each other, she in Chech, you in English

Thank you very much, both! I've changed the properties and it's finally in Czech ^^
And, Tarac, thanks for the tip, maybe I'll try it someday