My Furby's lips and body are moving, but making no sound?

The lack of sound is most likely the result of a loose speaker membrane. It can be remedied by pressing something against the speaker membrane to hold it in. It is also possible that the speaker may be broken, in which case the speaker should be completely replaced.

Assuming its a newer model:

You can check the wire contacts on the speaker and clean them, make sure all the wires are properly connected. If the wires are all connected to your furby/ furby boom, then you need a donor furby boom to swap out the speakers. They sell some pretty cheap broken furbys/Furby booms on ebay, that way the broken furby can use its working speaker in your furby to fix it. Furby and Furby boom's speakers are very similar and same in diameter. If this does not work, then the furby is paralyzed meaning the small 6V brushless DC motor went wrong.. You can replace it with one from a PC DVD reader (this is the door opener motor). Shaft is smaller but it's ok, diameter is good. You need a solder iron as well to replace electronic part from DC motor.

Hope this video helps: https://youtu.be/Xn5a07DFh9k

Replace new speaker diameter 36 mm then your furby working superb.. Becareful d-assembling

It’s mute but at least it works