Any of the bilingual teachers I can remember were native speakers of languages other than English and had accents that reflected their ethnicities.
http://amfix.blogs.cnn.com/2010/05/24/arizona-wants-to-reassign-teachers-with-accents/?hpt=C1
http://amfix.blogs.cnn.com/2010/05/24/arizona-wants-to-reassign-teachers-with-accents/?hpt=C1