I always like to frame this kind of thing using the term "appropriateness." We can imagine an amoeba having a rudimentary ability to detect whether its surroun

I always like to frame this kind of thing using the term "appropriateness." We can imagine an amoeba having a rudimentary ability to detect whether its surroundings are hostile or not and employ an instinctual response to evade it. It's not much of a leap from there to say humans have a social instinct, and that our ability to evade hostility has become strongly correlated with our ability to identify behaviors that are appropriate in context. And language is, in an abstract sense, just this: choosing appropriate actions. Maybe they're words. Maybe they're intonations. Or other social norms. Nobody learns 'just' language as a child, they learn a whole way of life. They learn "swearing is wrong," not simply "this is the proper syntax for swearing." And they feel its wrongness when they swear. You can't know what swear words mean if you can't feel that, and you probably won't be able to survive very well as a human if you can't determine what behavior is appropriate or not in your situation.