“Unlocking the Secrets: The Surprising Answers to Your Most Embarrassing Questions Revealed!”

“Chimpanzees communicate mainly by gestures and facial expressions. They do make noises, but they’re not the most important part like they are for us. Chimps only have four distinct noises, “grunts, barks, screams, and hoots”. The way they distinguish meaning from these is how loud they are and whether they’re low or high pitched.
So chimps don’t need the phonetic range that a human or a bird has. They don’t need their muscles to make the kind of complex sounds that humans use. Evolution made some changes to our anatomy that allow us to make a wide range of sounds, but chimps don’t need that so they never developed it.” —u/WarmerClimates