Here is a puzzle from the International Linguistics Olympiad (Stockholm 2010), an annual competition for budding linguists in secondary schools around the world. It requires no specialist linguistic knowledge, just a general linguistic intuition and a hefty dose of lateral thinking. But be warned, you’ll need more than a coffee break to do it!

 See the solution.

For more puzzles from the International Linguistics Olympiad, or for information about how your school can take part, see their website.