How to launch a 64-bit program with a different locale than the system locale?

It's more easy: This method works for all Windows 32bits or 64bits ;-)

• Create different new local users (one for each language).
• Log in with each user and change the Windows language of that account to the desired language.
• Log out (Repeat for each user).

When you finish the setup:

• Log in with your usual user.
• Run the application you want to see in a different language with the "Run As" method (Shift+right click on the shortcut and select Run as different User) using the user which has that language on his settings.

There's an open-source alternative to Microsoft AppLocale that is claimed to work up to windows 10, available on GitHub:

https://github.com/xupefei/Locale-Emulator

Its allows per-app locale settings, accessible via a context menu option.