Hindus - your preferred language?
What language do Hindus in India use to read their religious texts? Is it the local language (like Hindi) or the original language of the text?
Hinduism ancient texts are the Vedas which language is संस्कृतम् (anglicized as "Sanskrit"). These texts are translated in more than 22 Indian languages, including Hindi.
I don't know about Hindus, or Jains either, but Buddhists in India mostly use Pali, Sanskrit, Tibetan, and English.
Evam me sutam.
Evam maya srutam.
di skad bdag gis thos pa
Thus have I heard.
To confuse the matter further, Pali and Sanskrit have been written in about a dozen scripts each, and in more than a dozen romanizations each.
Sikhs traditionally read Sri Guru Granth Sahib in Punjabi, in Gurmukhi script, but I am sure that there are other practices.
The language originally used in religious texts is Sanskrit, which is written in the same script as Hindi, i.e. Devanagari. Pandits (priests) recite the verses or prayers in Sanskrit itself.
A lot of copies of the texts these days come with Hindi (and even other English language translations) for people to understand.
Hope this helps.