system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do our voices get higher in pitch when we are overcome with emotion?

Not in volume, but in pitch. This occurs across a range of emotions - whiny crying voice, squeaky elated voice, frightened screamy voice, etc.
gpt
It's because you tense up, which makes your vocal cords get tense also, which makes them vibrate faster, which makes your pitch go up. (Think about what happens to a guitar string when you wind it tighter. It's the same principle.)