Language--both oral and written--is an essential driver in the process of individual and national development. But languages are living things; they need to develop, thrive, and be used effectively--and many need to be revitalized and even saved from an early death--in order for all people of the world, especially those most excluded and disadvantaged, to benefit from development. But languages are in trouble. Linguistic diversity--as with cultural diversity and biological diversity--is under serious threat around the world. The world's small, ethnic-minority language communities represent a relatively large percentage of the world's illiterate population. Why is this so? In part, because ethnic minorities are often kept out of the mainstream of their nation's social, economic, and political life and institutions. They are let into that mainstream life--if at all--only once they leave behind their ethnic and linguistic identity and take on the language and culture of the dominant society--a society larger in numbers, richer, and more politically powerful. But to make sure that language remains the "strength" of ethnic minorities, their languages must often be further developed, even revitalized, and, above all, transmitted to future generations and used. it is essential that educational policymakers and planners, administrators and teachers, understand and appreciate that: (1) The diversity of a multi-ethnic society is a rich treasure to be exploited; (2) Learning the language of the home helps learning the language of the nation; (3) Literacy in both ethnic minority languages and the national language will promote greater national unity and loyalty; (4) Poor ethnic minority communities can become net contributors to development; and (5) Communities (provinces, districts, villages) need to have a significant influence on the governance of the schools.