December 15th is Esperanto Day. Esperanto is the artificial language created by Ludwig Zamenhof, in the 19th century. He spoke a number of languages and reassembled them to create a new one. 125 years ago this month, the first Esperanto dictionary was published. So what role does Esperanto play nowadays? Astrid Pietrus met up with Esperantists in the German city of Leipzig to find out more.