Don't talk about UP and Bihar culture. UP/Bihar was the cradle of Indian civilization. Hinduism, Budhhism, Jainism took birth and developed there. The Hindu culture, you have in Maharashtra, has its root in these states. Language is just one thing.
Bihar ditched the congress long back in the national interest. But Delhi, Himachal Pradesh, Maharashtra,Andhra Pradesh,Haryana,Goa and many more states are still ruled by congress led gov. Bihar has been neglected since British time. The Indian Rebellion of 1857 started in the Gangetic plain, mostly in Bihar ,eastern UP and central India. The people of this region suffered the most and they adopted anti-western stand. While the rest of India, including Bengal adopted English language , western knowledge and culture, the Hindi belt was opposed to anything western. After independence many of the Indian states saw the presence of sub-nationalism, which gave them a regional identity. While UP and Bihar till date has not regional identity. Sub-nationalism doesn't exists in these states and that makes them over look their regional interests.
