The 2011 Census counted 2,59,678 people with English as their mother tongue, 0.02% of India, because it asks for the language the person’s mother spoke to them in childhood. The Svarah authors estimate that about 10%, or 130 million, of Indians speak English, which is why accent is the real question. English is not in the Constitution’s Eighth Schedule; the Home Ministry lists it among 38 languages for which inclusion has been demanded. Article 343 of the Constitution kept English in official use for 15 years from the Constitution’s start and lets Parliament provide by law for its use after that. This is general information, not legal advice.
The Svarah paper asked speakers to say things like “Pay 1000 rupees from my SBI bank number … to UPI ID …” and to add named grocery items to a shopping cart. Those everyday-use prompts were the hardest: 11.2% for Whisper large, against 6.2% for read speech. The authors put it down to entities such as brand names, bank names, food items and document IDs. Office speech is full of them.
Whisper’s README lists about 1 GB of video memory for the base model, 5 GB for medium and 10 GB for large, and the paper’s base model nearly doubled the error rate on Indian accents. Model size is a real trade-off.
English with Hindi or regional words inside it is a separate test; see the Hinglish page. No source reports a result for it.