If you've played Chrono Trigger, you probably remember Ayla spoke in incorrect English ("Me Ayla!") to demonstrate the extent of her primitiveness. Actually the opposite is true; the more simple the society, the more complex the morphology tends to be. As a civilization modernizes, it tends to shed the many complicated aspects of the language. Take Latin and Spanish for example: Latin has a declension system that allows a speaker flexibility. Spanish lost that, and now like English parts of speech are dictated by a word's position in a sentence. Or look at English itself: Not only does Old English also have a declension system, it also had genders (masculine, feminine, and neuter) that are almost completely nonexistent today. So each time I see a caveman incapable of producing a complete sentence, I just giggle because god knows I'm happy nowadays we don't say a tree is a masculine noun or a gift is a feminine because that's what that caveman should be saying.