Summary: Esperanto is undoubtedly the best known and most successful invented language but it's far from the only one. Richard Langston talks to Arika Okrent who lists 500 of them in her book 'In the Land of Invented Langauges'; and Jeremy Rose speaks to John Quijada the American inventor of Ithkuil, a language that has developed a devoted following in Russia, and David Ryan, a member of the New Zealand Esperanto Association.
