Why does your voice get deeper when you are tired?

Probably because you’re not putting enough effort into your speech.

When I get this way, I end up sounding like a haggard Russian man that’s been smoking for years.

Are you more relaxed, perhaps? Therefore the vocal cords would be less “taut”, making your voice deeper…

Does it?

I think yankeetooter’s answer sounds reasonable. Also, any use of the word taut in a non-sexual setting is rare.

Maybe you’re hitting puberty.

I think the vocal cords are more relaxed and possibly respiration is deeper too.

Vocal chords are dry

It relating to how much oxygen does have.

@josie Dry would be raspy right? Is that the same a deep?

@JLeslie
OK then, muscles in larynx get fatigued, can’t stretch vocal chords as tightly, they vibrate at a lower frequency.

Also why our choir director tells our sopranos (well, everybody) to get plenty of rest before singing…you just can’t hit those high notes otherwise….

You’re probably relaxed, but I don’t know could be other reasons.
(Sorry that link was directed @Kate) :D

@josie latest response makes sense too.

@josie That makes sense.

I think it’s because you’re more relaxed. My voice is deeper after yoga class. It’s great that you made that observation. Sometimes when people get high-strung, their voice goes up really high; when their stance softens up, so does their voice.

There’s a whole science to vocal articulation, speech production, and breathing.