1. Tried it on whatsapp web and didn't work.
2. Trying to figure out how it's supposed to work is difficult.
3. Even if you try to select a language you just cannot select it. The moment you close the small dialogue box of the extension the selected language is reset.

did not work for Hindi. Choosing Hindi option provided predictions of Sinahalese or some other unknown language. Probably needs to be debugged. Tried on Latest Firefox on Fedora 42 KDE