Question

how did the people belonging in different communities, regions or language develop a sense of collective belonginf during the indian freedom struggle

Answer 1

As people of different communities has been brought about by mahatma gandhi. They all had a same motto that is to get freedom for British so they all joined together to fight for a same cause.
This was same cause for them as they all were suffered by British. ex: flogging of people, imposition of tax. This made them to make a collective sense. There was also another reason for this that is people thought that a unique community cannot fight against British. so they joined together.