@Geoflame14 Press the X button on the controller.
Enter the settings from there. It can be found under the profile picture/icon at the bottom right of the icon.
While in the settings section, highlighting the system will give you the option to show the language and location. Language Click the icon that says English. Then scroll to Japanese.
Once this is done, restart your xbox and load Apex. If Apex is still in English, try uninstalling and reinstalling Apex. The Japanese pack may be downloaded due to the switch.
If that doesn't work, let us know.