You can enable TTS upon clicking words and phrases in Hindi by enabling Speaking Mode from the Settings page. (This is a Premium only feature.)
You may also have Hindi TTS available for the Read Aloud feature but only if your device has Hindi voices available for web-apps to use via the web speech API. (Unfortunately iOS support for this seems to have gotten worse with the update to iOS 18, with some voices no longer available)
Thanks, I think there is some wrong information displayed on the site. When I am not subscribed and go into settings underneath speaking mode it says something like “Speaking mode is supported by 23 languages, but unfortunately not Hindi”, however when I click on subscribe, Hindi is listed as one of the supported languages in the info panel. Also now that I am actually subscribed, when I go into setting it now says “Speaking mode is supported by 23 languages, including Hindi”. This must be a website bug