I know some guys hear are historians and u/AlfredicEnglishRules is an anthropologist. I was listening to a podcast and someone brought up some groups in America use slang predominately because their biology makes English difficult for them. I'm wondering how biology affects language? Is it just an IQ thing, or are there subtle differences in vocal chords? Or is it bullshit?
I can understand cultural differences shaping languages. And I've heard evolutionary differences, like early men having to increase their vocabularies to include dogs in their hunting.
Intelligence definitely shapes language. And intelligence shapes individual biology and biological outcomes. So, yes, it's entirely possible that there are subsets of the human population that simply cannot use modern languages effectively, because their brains just cannot handle the word/object, concept/individual or reality/possibility differences. (For instance, a lots of blacks will call everything of a type by a brand name withing that type "Glock brand glock" and cannot distinguish hypothetical and reality-based questions "but I did eat breakfast yesterday!")
Culture also effects language, to a degree that modern Westerners probably cannot comprehend. It's also entirely possible that individuals within un-advanced/regressed cultures have never gained/have lost certain language abilities.