There is a correlation between language proficiency and achievement in mathematics (Riordain & O'Donoghue, 2009), and this is particularly evident for children who speak English as an additional language or dialect. More effort needs to be made in mathematics classrooms to develop cognitive competencies, including the ability to decode and encode mathematical problems, and use appropriate mathematical language when doing so (Turner, 2011). Although the mathematics teacher has much content to deliver, mathematics content is delivered through language and so all mathematics teachers are teachers of the language of mathematics. Yet, this is a language that has become invisible and intuitive to the teachers of mathematics but which remains invisible and confounding to their learners. Gough (2007) makes the worrying observation that when teachers are not aware of the language ambiguities and challenges in mathematics they fail in their teaching responsibilities and instead lay the blame at the feet of their students, quoting "'learning difficulties', cognitive confusion, attention deficits" (Gough, 2007). The consequence is that learners struggling in the mathematics classroom are misdiagnosed, and presented with ineffective or irrelevant interventions. When students are left to struggle, with their challenges misunderstood, their achievement levels in mathematics continue to drop along with their opportunities for positive post-school outcomes (Fuchs et al., 2012). If the national curricula and Core Standards in countries around the world are to make good on their claims to promote excellence and equity in education then mathematics teachers must take up the challenge and teach both the content and the language that is specific to Mathematics.