Mathematics classrooms are increasingly multilingual, whether they are found in linguistically diverse societies, urban melting pots or planned bilingual programs. The chapters in this book present and discuss examples of mathematics classroom life from a range of multilingual classroom settings, and use these examples to draw out and discuss key issues for the teaching and learning of mathematics and language. These issues relate to pedagogy, students’ learning, curriculum, assessment, policy and aspects of educational theory. The contributions are based on research conducted in mathematics classrooms in Europe, South Asia, North America and Australia. Recurring issues for the learning of mathematics include the relationship between language and mathematics, the relationship between formal and informal mathematical language, and the relationship between students’ home languages and the official language of schooling.