My active interest in bilingualism and bidialectalism started in April 1969, when I took up my first teaching post at an inner-London secondary school. Having received no formal teacher training and having had only a very limited experience of secondary schooling after attending a boys’ grammar school from the age of eleven to eighteen, I took into this post a common-sense and, with the benefit of hindsight, profoundly flawed notion of what teaching and learning ought to be about. This included perceiving surface errors in my students’ written work as symptoms of laziness, slovenliness or plain stupidity (at any rate, as unsightly blots deserving of the most rigorous red-inking at my disposal), and seeing any differences at all between my students’ performance and ‘standard’ English practices as deviations that must be rectified instantly and without explanation. Mine was an unquestioning acceptance of the received cultural practices of school and academic life as the only right cultural practices, and of other cultural practices as simply gone-wrong versions of that standard.