That is done too. It works in both directions. What you’re describing is a microphone. A quartz crystal is vibrated and it generates an electric signal. If you play that electric signal back into the crystal it reproduces the sound, aka a speaker. The design of the two change obviously to improve quality for their purpose, but if you have a headset or something with a 3.5mm jack with separate mic/speaker inputs, try plugging them in the opposite way. Your mic will start playing sound and your speaker will produce input when it hears things.
That is done too. It works in both directions. What you’re describing is a microphone. A quartz crystal is vibrated and it generates an electric signal. If you play that electric signal back into the crystal it reproduces the sound, aka a speaker. The design of the two change obviously to improve quality for their purpose, but if you have a headset or something with a 3.5mm jack with separate mic/speaker inputs, try plugging them in the opposite way. Your mic will start playing sound and your speaker will produce input when it hears things.