internal speakers not working

Most often it's due to something messing the headphone jack up, but...

Have you done a PRAM reset, CMD+Option+p+r...

Reset NVRAM on your Mac - Apple Support

In fact, do 3 in a row, takes a bit of time.

Intel-based Macs: Resetting the System Management Controller (SMC)...

Reset the SMC of your Mac - Apple Support

For troubleshooting try plugging headphones into the Mac audio socket. Do they work? If not go to 🍎/Settings/Sound and see if the Mac has found speakers/headphones. Also check the volume is not zero.

Great news, take care my friend. :)