Here is an interesting new book, by Jacqueline Mowbray: Linguistic Justice: International Law and Language Policy (Oxford 2012). From the abstract:
Globalization and migration are producing societies of increasing linguistic diversity. At the same time, English is achieving unprecedented global dominance, smaller languages are becoming 'extinct' at an alarming rate, and ethnic tensions in countries from Belgium to Tibet continue to centre on questions of language. Against this background, the issue of how to ensure justice between speakers of different languages becomes a pressing social concern. Matters of 'linguistic justice' are therefore drawing increasing scholarly attention across a range of disciplines.
How does international law contribute to linguistic justice? This book explores that question by conducting a comprehensive, interdisciplinary examination of international law on language ... the book explores the conceptual framework which underpins international law on language, unearthing underlying assumptions and ideas about what constitutes a 'just' language policy from a legal perspective. ..This explores an interesting aspect of international society and culture. More at the link.