I learned a fascinating detail in my phonology class that was relatively peripheral in terms of the lecture, but interested me enough to do my own research on it afterwards.
If we look at this diagram of the ape's mouth and trachea compared to a human's, we can see that the length of the pharyx in apes are a lot shorter than the human pharynx. This in apes helps to prevent choking on food, since both the respiratory system and the digestive system are trying to use the same mechanisms to get their job done.
If we look at this diagram of the ape's mouth and trachea compared to a human's, we can see that the length of the pharyx in apes are a lot shorter than the human pharynx. This in apes helps to prevent choking on food, since both the respiratory system and the digestive system are trying to use the same mechanisms to get their job done.
Ape on left, human on right.
How is it beneficial, then, to let humans develop a longer pharynx and thus a greater choking hazard? This longer length of the pharynx allows us to make the range of sounds that are together human speech. Apparently speech and communication is so important to us that it's worth the extra choking risk.
Although, one precautionary measure built in to our development is that infants, too, have a small pharynx, allowing them to simultaneously breathe and drink milk. (This is such a cool fact - I tried to drink and breathe at the same time for a little bit after I learned this and ended up nearly choking, so yep, it's true about the increased pharynx length). However, once they reach about 18 months the pharynx lengthens. This is also around the time that children begin their word burst, when their knowledge of language grows exponentially. Coincidence? I think not.
