system
Given the following post, respond as if you're commenting on Reddit:
human
[General Scifi] Why can you talk through a prison force field.

In most settings there are no intercoms in the cells and they can just talk right through it.


Most of these cells even have a separate air supply, so it is not air circulation.
gpt
The particles that make up the forcefield still vibrate when the soundwaves hit them, transferring the energy to the air molecules on the other side and allowing the sound to keep traveling. 

Same basic principle of talking to someone through a glass window, only in this case the 'glass' is extremely thin so not as much energy is lost in the transfer from one medium to another, so the voices don't sound muffled.