VocabHang

VocabHang is a vocabulary tutor you talk to. Press a button in your browser and have a real conversation, in a natural voice, about your work, your city, or anything you bring. While you talk, it figures out which words you know, adds the ones you're missing when appropriate, and brings them back in later sessions until you use them yourself. It gives you your level as an honest range on the CEFR scale, explains any word you ask about, and never interrupts you to correct grammar. Try it without an account; signing in gives 30 free minutes a day. The interface is in eight languages; the tutor speaks English. It is in public beta.