We have society, schooling, media, art, and culture; and every human is unique and individual thanks to thousands of years of these. Even if we got a fruit fly

We have society, schooling, media, art, and culture; and every human is unique and individual thanks to thousands of years of these. Even if we got a fruit fly to speak, it's likely that every other fruit fly will say very similar things as they just have the genetic code but no "culture." So I think the difference here is caused by society, not by simplicity. Each human carries the combined knowledge of ancestors.