Tuesday, October 5, 2010

Chimp vs. human vocal tracts

I may write more about this later, but for now just examine the differences.

Later... (added on Oct 9, 2010):

Essentially, in apes the larynx is higher and the epiglottis can lock with the velum; in humans the larynx is too low for this to happen. Also, ape tongue movement is mostly in-out, while humans can move the muscle up and down as well as in-out. Furthermore, the tube through which air passes from the glottis out to the lips is gently curved in apes, but in humans it forms a right angle. Anyone who plays any kind of wind instrument knows that different shapes produce different sounds.

What all this means is that apes (and human newborns, who are similar) cannot produce sounds with the acoustic properties of adult human speech. And it's why it was such a stroke of genius to try out manually-produced sign languages on them.


  1. Hi, I am doing a presentation on the Evolution of Speech at school, I was wondering if you could write a bit more about the mechanics of ape speech/calls. Am looking at apes, and using this as an example as to how we may have been a few 100,000 years ago. Thanks

  2. Hi Anonymous, This is a bit old but Lieberman is/was very good on this subject.


    You might also check out his book The Biology and Evolution of Language (Harvard UP 1984. Again, dated but the the stuff in it is good.

  3. I am also interested in this, not for school, but for my own understanding of human speech and how it began.


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