This study is the expanded version of the advocacy brief "Mother Tongue-Based Teaching and Education for Girls" [ED495413]. It highlights in more detail the correlations between girls, language and marginality, and shows that there are indeed positive links between the use of mother tongue in education and female participation and achievement in learning. While many challenges remain, the use of mother tongue in education has powerful pedagogical and social justifications and, thus, is a critical step in the right direction towards achieving Education for All. This paper argues that one of the principal mechanisms through which inequality is reproduced is language, specifically the language used as the medium of instruction. It shows how the learner's mother tongue holds the key to making schooling more inclusive for all disadvantaged groups, especially for girls and women. Contents include (1) Introduction; (2) Connections Between Language and Marginality; (3) Connections Between Girls, Language and Marginality; (4) The Proposal: Mother Tongue-based Bilingual Education; (5) Obstacles to Girls' Participation and Strategies that Address Them; (6) Mother Tongue-based Schooling as an Effective Strategy for Addressing Girls' School Participation; (7) Conclusion; (8) References; and (9) About the Author. The Conclusion sets out nine strategies that may provide the impetus for more far-reaching reform by demonstrating positive effects. Some examples are:(a) Getting local and national ministries of education to authorize oral mother tongue use in the classroom, especially where it has traditionally been prohibited; (b) Changing teacher placement practices so that teachers come from the same linguistic group as their students, a measure which is likely to increase the number of female teachers because they can stay in or near their home communities; (c) Implementing mother tongue-based teaching at the preschool level, which may be easier if preschools are less controlled by official structures; (d) Providing in-service training for teachers in first and second language development, themes which should be taught wherever there is linguistic diversity; (e) Providing for study of the mother tongue as a discipline, which involves no change in medium of instruction for other subjects in the curriculum; (f) Working with teachers and communities to operationalize local curriculum components of school programs; (g) Organizing extracurricular mother tongue-based language clubs; (h) Getting school children involved in local radio programming; and (i) Encouraging family members participating in mother tongue-based literacy classes to share their reading and writing skills. These and other measures that do not involve large-scale transformation of educational systems are likely to promote awareness and prompt participants to reevaluate traditionally marginalizing practices at school.