Long term impact is what really matters. However longitudinal research is rare. The Young Lives Project is a long-term international research project"investigating the changing nature of childhood poverty". India has been chosen as one of their focus countries. The question is asked: "What does the future hold for the 2000 Young Lives index children born in the state of Andhra Pradesh?". As mother tongue is part of the data documented, this research is also relevant to language and education issues.
Some findings of the 2008 second round of survey in India http://www.younglives.org.uk/countries/india/index_html:
"We found that household and community characteristics greatly influence children’s outcomes, particularly ethnicity, the rural-urban divide (which affects access to services among other things) and parents’ levels of education. Household wealth is an important determinant of child outcomes.Interestingly, maternal education has a stronger impact on nutrition,while the father’s education is a more important determinant of enrolment. "