1) India has immense linguistic diversity with over 1600 languages spoken, though many are spoken by small groups. The 1971 Census found 281 languages spoken by over 5,000 people each.
2) Historically, languages like Sanskrit, Pali, Persian, and English influenced India under different rulers. Post-independence, several commissions recommended policies like using the mother tongue as the medium of instruction and establishing the three-language formula.
3) The Indian Constitution designates Hindi as the official language but allows English to be used for official purposes. It also requires states to promote the mother tongue and Hindi. The three-language formula incorporates the mother tongue, Hindi, and English or another modern Indian language.