Before attempting advanced methods, try the native menu. This will only work if your specific F-04J was updated with a multilingual build (rare, but possible).
: Go to your phone's device settings, tap About Phone (端末情報), and tap the Build Number (ビルド番号) exactly seven times until a toast notification confirms you are a developer. change language in fujitsu f04j docomo full
This changes the Settings, Notification shade, and system apps only if the language exists in the ROM. For 95% of users, languages beyond English/Japanese/Chinese will not be here. This is the end of the "full" stock experience. Before attempting advanced methods, try the native menu
If your phone reverts back to its original configuration after a restart, your system cache might be locked by Docomo's optimization framework. To fix this, update your device's firmware to the latest available revision over Wi-Fi. Alternatively, use and keep the app running in the background. Google Apps Stay in Japanese This changes the Settings, Notification shade, and system