Language preferences may change due to system default settings or individual preferences being updated. Here's how you can set your display language back to your desired option:
Click on your profile icon in the upper right corner of your screen.
Choose 'Change Language'.
Select your preferred language from the list.
This should reset your language preferences accordingly. Keep in mind that if there's a default language set by your organization, or if automatic updates occur, this may affect your settings. Your language preferences will synchronize across other platforms once you've made these changes.