India has a single dominant language continuum - Hindi.
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I don't think that Hindi is serving as a unifying vehicle. It is spoken by only one third of Indians and it was chosen as national language by just one vote. The opposition to Hindi became stronger after it was designated as the national language. It is not only the speakers of Dravidian languages that oppose the imposition of Hindi but the speakers of Bengali, Punjabi, Marathi etc. are also against the domination of Hindi.
Marathi people consider themselves as North Indians and they would have not preferred to be a part of the South in 1947. But if the choice is in 2017 I think they would opt to be a part of the South India. This is because of the comparative progress made by the southern states in recent years. The Hindi speaking states of Rajasthan,Uttar Pradesh, Madhya Pradesh, Bihar, Jharkhand, Chchathisgarh etc. are far behind in social and economic development when compared to the South. The average PCI of the South India is double that of the North India.