For that, I turned to my favorite commentator on language, author Michael Erard.

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To find out whether anyone could really learn so many languages, Mr Erard set out to find modern Mezzofantis.

ECONOMIST: What makes some people learn language after language?

He chose the Erard, a French piano with greater power and tone, but still far from the sound he sought.

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Mr Erard says that true hyperpolyglottery begins at about 11 languages, and that while legends abound, tried and tested exemplars are few.

ECONOMIST: What makes some people learn language after language?

In the end Mr Erard is happy simply to meet interesting characters, tell fascinating tales and round up the research without trying to judge which is the best work.

ECONOMIST: What makes some people learn language after language?

Mr Erard repeatedly peppers his text with such questions, feeling his way through his story as a thoughtful observer, rather than banging about like an academic with a theory to defend or a pitchman with a technique to sell.

ECONOMIST: What makes some people learn language after language?