So for some strange reason, your audio has stopped playing through the Macbook Pro speakers, but if you plug in an external audio device, it still works? Or perhaps some other undesirable combination?

If so, you could just try restarting the computer. That usually fixes thing right?

But you have all those million apps open, all in unsaved states.. So rebooting is not the preferred approach.

Try the below option to give your Apple the kick it needs!

How to restart your sound drivers on Mac

Open up a Terminal window, or iTerm if you’re cool, and run the following:

sudo kextunload /System/Library/Extensions/AppleHDA.kext
sudo kextload /System/Library/Extensions/AppleHDA.kext

Sometimes it helps to kill the coreaudio as well..

ps aux | grep 'coreaudio[d]' | awk '{print $2}' | xargs sudo kill 

Did that work?