Why did English become a first language in some Commonwealth countries and a second language in others?

English became a first language in some Commonwealth countries, such as Canada, Australia, and New Zealand, due to the colonization by English-speaking countries. In other Commonwealth countries, like India and Nigeria, English became a second language due to colonization but didn't replace the native languages as the primary means of communication. The varying degrees of influence and cultural assimilation played a significant role in shaping the status of English in each country.