The pupils were chatting away but neither of the two teachers had to raise their voice. Anyone who has had to sit through the tedium of classes in Japan, where normally you can hear a pin drop, would have felt green with envy.

“That doesn’t look right. How about changing this word?” one pupil says to a classmate in English. “Why don’t we make the photos bigger for the presentation?” says another in Japanese.

The nine to 11-year-olds were collaborating while switching between English and Japanese — an everyday scene at the New International School of Japan in Tokyo. “If you visit any other international school, some have signs saying ‘Speak English’,” says Steven Parr, the headmaster. “Language-use rules are very common. Usually they say ‘speak Japanese only in the Japanese class and speak English everywhere else’.”