The new feature will be available in one-on-one chats, group chats, and Channels. To translate a message received in a foreign language:
Long-press the message.
Click the "Translate" option.
Select the language you wish to translate into.
Android users will also have the ability to automatically translate entire chat threads. Additionally, offline use will be possible by downloading translation packages.
WhatsApp has clarified that the translations are performed entirely on the device, and no data is sent to servers. This guarantees that the company cannot access the translation data and that conversations remain private.
The initial language support is as follows:
Android: English, Spanish, Hindi, Portuguese, Russian, and Arabic.
iPhone: Broader coverage with support for over 19 languages.
The company announced that more languages will be added in future updates.