system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does everyone have such distinctive voices when the make up of our throat area is very similar?
gpt
Trained as a linguist here.

"Similar" is only in the most basic terms. People vary a lot. 

More importantly, our brains are specifically attuned to speech, and we can perceive very *very* subtle differences. Like, a timing difference of 30 milliseconds, and a pitch difference as low as 1 Hz at 200 Hz (male speaking voice).  

We are sensitive to a fraction of a millimeter's difference in placement in consonants (think of the difference between where your tongue lands when you say T and CH).  We are sensitive to less than 100 Hz differences in vowels, or a fraction of a millimeter (think of how close the difference is between the "e" in DRESS and "a" in FACE in terms of where your tongue is to make the vowel). 

"Distinctive" comes from all kinds of things including fundamental pitch (vocal chord length), pitch changes (relative pitch), stress (relative loudness), vowel placement, consonant articulation placement, speed, timing, accents, "sets" of the tongue and jaw and soft palate, and other social things people do with their voices, consciously and unconsciously, to show they're part of a group. 

Voice identification to one individual is actually very difficult. In court settings, people get it wrong a lot.  

TL;DR - We are very, very, very sensitive to subtle differences in speech, and people do lots of things to differentiate themselves.