Why does the pitch of my voice fluctuate depending on these circumstances?

It could be a girl thing. Same thing happens to dudes who are not quite yet men.

your voice gets deeper because you’re tired, plain and simple. your vocal chords are getting lazy and not tightening up as much.

your voice gets higher when you’re nervous because it’s a sign of passivity, your subconscious is letting who ever you’re speaking to that you’re not trying to be threatening, it’s just a defense mechanism.

@Zendo that couldn’t be much farther off. you’re voice raises and lowers as well, you just have a naturally deeper voice so it’s more subtle.

Your tone is controlled by the muscular contraction of the vocal chords. If those muscles are tired, tense, or relaxed, it affects the sounds being produced by the larynx.

Sometimes I wish the fluther mods would let the asker see the removed responses. My interest is piqued. :)

@ABoyNamedBoobs03: GA! I kind of figured that nervousness lead to tightening of vocal chords through muscle tension (like your whole body when you’re stressed) but never thought of it as a defense mechanism.

@ABoyNamedBoobs03 Thanks big boy! Good luck on the date. Try not to let your voice fluctuate…LOL