Open WhatsApp
Tap the chat box to bring up the keyboard
Tap the keyboard language key or globe icon
Select the language you want
If the language is not available, open your phone’s keyboard settings
Add the desired language to your keyboard
Return to WhatsApp and switch to the added language
On Android, you can also change the keyboard language from Gboard settings
On iPhone, go to Settings > General > Keyboard > Keyboards and add a new keyboard
On Android, go to Settings > System > Languages & input > On-screen keyboard > your keyboard app > Languages
Restart WhatsApp if the new language does not appear