JAVIER is a JAvascript Voicexml InterpretER, designed (but not restricted) to run inside a web browser, its main engine has less than 1000 lines of code. It's maybe, the tiniest but (almost) FULL VoiceXML implementation.
I heard about a method where you can learn 1000 words in a year with 10 minutes of daily effort.
This program does organize, and divide the words in daily chunks.
It is a module for Lepton-CMS or WebsiteBaker