Blender: Make Your Own Furby | Tutorial 

Furbies have an internal battery that is used to keep a little of the battery juice so it could retain what level of english it was at. By keeping the batteries in all the time, the internal battery became overcharged so it would start working when it wasn't supposed to. Even if you took the battery out, it would of still talked because the internal battery had plenty of charge. This was a very common problem. My grandpa used to take the batteries out every time my grandma stopped playing with her collection of Furby. My older sisters had furbies as well.... lets say they developed the odd habit of calling everyone bad words.