The threat seems to use the headphone/microphone jack and reverse them via software. This threat does not appear to utilize the outbound connection of the internal speakers.
That being said, we could consider offering a disconnected (meaning unplug the microphone, internal speakers, webcam) fairly easily as mentioned by Someone. This would not remove the threat linked to above (external headphones plugged into the headphone jack utilized as a microphone).
We could consider a ‘speaker’ kill switch that severs audio out from headphone jack and speakers…