Chatter Jammer is based on the 2012 Ig Nobel prize winning research, Speech Jammer. It will record your voice and replay it back to you at an adjustable delay. This is known as Delayed Auditory Feedback (DAF) and results in difficulty speaking. Chatter Jammer also has a list of suggested phrases to say and will record the 3 most recent recordings.
For proper usage, plug in ear/headphones and turn up the volume.