Here's the breakdown:
* Kokborok is a Tibeto-Burman language. It belongs to the Bodo-Garo branch of the Tibeto-Burman family.
* Meiteilon (Manipuri) is a Sino-Tibetan language. It belongs to the Kuki-Chin-Naga branch of the Sino-Tibetan family.
* Mizo is also a Sino-Tibetan language. It belongs to the Kuki-Chin-Naga branch of the Sino-Tibetan family, specifically to the Zomi subgroup, which is related to the Chin and Kuki languages.
Therefore, Kokborok is NOT a category II language. It is part of the Tibeto-Burman language family. Meiteilon and Mizo ARE category II languages as they belong to the Sino-Tibetan family.
The term "category II language" is often used in India, referring to languages that are not listed in the Eighth Schedule of the Indian Constitution. This means they may not have official status or government support in the same way as the Scheduled Languages.