The Mughal's were heavily Persianized and Persian was the court language, the preferred language of the Muslim elite in northern India, and generally the lingua franca of most of India until the British arrived.
One of our resident linguists can comment better but I believe Urdu and Hindustani are Indian languages with a Persian, Arabic, and Turkic vocabulary. The extensive use of Persian words in Indian languages indicates that a significant portion of the subcontinent spoke it at some point if only as a second language.