I was really surprised; Hindi is the third-most spoken language in the world, trailing only Mandarin and English. Of the top 10 languages in this Wikipedia list, Tor Browser is missing localizations only for Hindi, Bengali, and Malay. (Urdu is #11.)
https://en.wikipedia.org/wiki/List_of_languages_by_total_number_of_speakers
There is a simple reason for this and while this may be anecdotal, this may shed some light on why there are no Hindi or Urdu translations of open source software: almost all users I know whose native language is Hindi, Bengali (or other Indic languages), use their OS and other software in English. (English is the official language of India and Pakistan, along with Hindi and Urdu respectively.) I am sure other users from India/Pakistan can back this up, but personally, even though my native language is Punjabi and Hindi, I have always selected "English" when installing Debian. Similary, I have almost never seen a copy of Windows in any of the local languages, anywhere in India.
The English precedence is slowly changing though, with more and more technology products being shipped in local languages so that they can reach populations that don't speak English (which is more in number than the population that can.)
So while my experience with this has been different from Griffin's in that no Tor user in India has asked me for a translation in their local language, I think the simple reason may be that English-speaking population doesn't feel the need and right now, they are the ones that dominate the online market. Not that this is an excuse for not having local translations, but I am stating the probable reasons for the lack of translations.