I've been to several pow-wows in Minnesota and Wisconsin and all the singing I've ever heard was in native languages, not English.

A song and dance to honor veterans and relatives of deceased veterans has been an important feature of every pow-wow I've seen.

AIROS (American Indian Radio On Satellite), and Native American Public Telecommunications might be good places to start if you want to explore native music. They have a long list of links to other Indian organizations and resources, including musicians and record companies.