Why are Assamese, Hindi, and English used in Arunachal Pradesh?

In Arunachal Pradesh, the use of Assamese, Hindi, and English as lingua francas is necessary due to the state's immense linguistic diversity. The region is home to dozens of distinct ethnic groups that speak approximately 50 different languages and dialects, most of which belong to the Tibeto-Burman branch of the Sino-Tibetan language family.1

Because these indigenous languages are often mutually unintelligible, these three languages serve as essential tools for communication between the various tribal groups and the broader population.1