MacBook Air 2017 not recognising internal speakers

My girlfriend's MacBook Air recently stopped playing sound through the internal speakers. Looking at the sound preferences it isn't showing internal speakers as an option only the headphone port with no way of changing back to internal speakers.

When plugging headphones into the headphone port it you can only hear a faint white noise.

Connecting to a Bluetooth speaker still works and is currently the only way to play sound out of it.