There are many foreign celebrities here who speak Japanese to a high level, yet when it comes to 発音 (hatsuon, pronunciation) and 抑揚 (yokuyō, intonation), few sound as accomplished as Natalie Emmons. An American singer/songwriter who used to live in Osaka, she made a bit of a name for herself last year thanks to a series of commercials for the hotel metasearch engine Trivago.

Delivering phrases such as ホテル料金比較サイト (hoteru ryōkin hikaku saito, "a price comparison hotel website") in a native-like fashion, she had many people thinking the adverts were dubbed. They definitely weren't. The few Japanese sentences she spoke during our interview made that clear. So how has she managed to become so proficient in the language?

"I've been focusing on 文法 (bunpō, grammar) a bit more recently, but basically I've always been more of an audio-visual learner than a textbook one," she says. "It's like when you're a child — your own language develops naturally from the environment around you, then later you go to school and learn why it's structured that way.