Mother Tongue UPSC relevant
The census defines mother tongue as 'the language spoken in childhood by the person's mother to the person.' If the mother died in infancy, it is the language mainly spoken in the person's home in childhood; for infants and deaf-mutes, the language usually spoken by the mother is recorded; in case of doubt, the language mainly spoken in the household.
Crucially, it is recorded exactly as returned — mother tongue need not match any official language, and a person's mother tongue may differ from the language they speak best. Raw returns (over 19,500 distinct names in 2011, per news reports) are later rationalised and classified into languages by ORGI's language division. Census 2027's language data will drive the Eighth Schedule debates, linguistic-minority safeguards and education policy.