why did the english want the indians to be civilized and taught hindi when they came to india?they were talking their own language.suppose if india was powerful and they wanted the englishers to be taught hindi?

The British identified grave errors in the knowledge of the east which they believed was unscientific and regressive, it was light hearted and non serious. This is evident from the beliefs of the Anglicist like James Mill who criticized Orientalist views and argued that it was only through western learning we could civilize Indians as western education was modern, scientific and secular in its outlook. The British declared their objectives for introducing western English education as:

a. To civilize India.

b. To spread Christianity.

c. To consolidate British's power and position in the country.

d. British wanted to establish their cultural domination with spread of English language.

e. To serve their economic interests as English education would convince Indians about the superiority of British goods which were machine made, it would make Indians recognize the advantages of trade and commerce.

f. English education would create a class of people who could be part of civil service and serve their administrative purpose.

Had India been that powerful, India would not have been a colony. British took advantage of India's political instability, lack of unity to establish control over it. And yes despite being a colony, there were a class of British who showed interest in Indian Languages and culture. For example, William Jones.