lernu! is a free, multifaceted online resource for learning the synthetic language Esperanto. In addition to a series of story-driven lessons that test and reinforce your learning with a variety of interactive exercises, there’s a multimedia library with stories and music for Esperanto learners at different levels. Human narration is used throughout to teach you Esperanto pronunciation. The language’s grammar and pronunciation are explained succinctly, with expanded notes for those who wish to dig deeper. There’s also a social aspect, with an active forum and the chance to befriend other learners online. The only thing that seems to be missing is a speaking component.