If your phone refuses to create sound after you unplug it from a Bluetooth accessory, turning Bluetooth on for a few seconds and then off sometimes assist. It's conceivable that the phone still believes it's paired or connected to Bluetooth, in which case you'll need to clear its memory. Here's how to do it:

1. To access the Settings menu, tap the gear icon.
2. Toggle on Bluetooth.
3. Then, to turn the function off, tap the Bluetooth switch.