This is Nester. To teach Nester, just type a sentence into the ask bar and wait for Nester to respond, He will probably say gibberish, but if you spend long enough, he might say something clever.
This project was inspired by a project called Mimi learns from you, by puttering. This is a version that creates connections of letters instead of words. You should check out the Mimi project because it will probably say more sensible things, but this robot will invent new words that you may have never seen or heard before. Mimi learns from you: http://scratch.mit.edu/projects/16714501/