Apes can't speak! The biggest fiction in the Planet of the Apes movies isn't Charlton Heston time traveling, it's all the apes yapping up a storm. They simply don't have the vocal ability.
OR DO THEY?
Scientists gave some gibbons helium. Why? Because you have helium and you have apes and eventually somebody was going to think to put them together. But beyond cute hilarity, what the scientists discovered is that the heliumanated apes used their vocal chords in a complex way similar to how opera singers do.
"The complexity of human speech is unique among primates as it requires varied soft sounds made by the rapid movements of vocal tracts," lead researcher Takeshi Nishimura, from the Primate Research Institute at Kyoto University, said in a statement. "Our speech was thought to have evolved through specific modifications in our vocal anatomy. However, we've shown how the gibbons' distinctive song uses the same vocal mechanics as soprano singers, revealing a fundamental similarity with humans.
"This is the first evidence that gibbons always sing using soprano techniques, a difficult [vocalization] ability for humans which is only mastered by professional opera singers," Nishimura said. "This gives us a new appreciation of the evolution of speech in gibbons while revealing that the physiological foundation in human speech is not so unique."
So while this doesn't exactly equal apes evolving from men, it does indicate that perhaps vocal communication is possible with apes. Caesar home, indeed.
Here's the money sound:
And here's a gibbon hugging Cragen on a particularly weird episode of Law and Order: Special Victims Unit: