Nearly five decades ago Potti Sreeramulu had sacrificed his life, with his fast unto death for 'Telugu' speaking state and in process broken Jawaharlal Nehru's resolve.
Those from Andhra had been more successful, they felt. Reddys, no doubt, had money and wielded more clout. This is another reason that Andhraites want Hyderabad to remain a joint capital. As far as status of Hyderabad as joint capital or union territory is concerned, it is not practical as the City is not on border like Chandigarh [which touched both Punjab and Haryana] but in the heart of Telangana and far away from Andhra.
[*Personally I don't like the term 'Regional language'. Especially, for languages spoken by tens of million which even internationally have more speakers than many of the big languages.]
[**Bangla is also one of the state languages in Tripura along with Kokborak and Manipuri but it is comparatively a small state]