Language is a purely human and non-instinctive method of communicating ideas, emotions and desires by means of a system of voluntarily produced symbo… - Edward Sapir

Were a language ever completely "grammatical" it would be a perfect engine of conceptual expression. Unfortunately, or luckily, no language is tyrannically consistent. All grammars leak.

Human beings do not live in the objective world alone, nor alone in the world of social activity as ordinarily understood, but are very much at the mercy of the particular language which has become the medium of expression for their society. It is quite an illusion to imagine that one adjusts to reality essentially without the use of language and that language is merely an incidental means of solving specific problems of communication or reflection. The fact of the matter is that the "real world" is to a large extent unconsciously built upon the language habits of the group. No two languages are ever sufficiently similar to be considered as representing the same social reality. The worlds in which different societies live are distinct worlds, not merely the same world with different labels attached … We see and hear and otherwise experience very largely as we do because the language habits of our community predispose certain choices of interpretation.

Getting down to brass tacks, how in the Hell are you going to explain general American n- 'I' except genetically? It's disturbing, I know, but (more) non-committal conservatism is only dodging, after all, isn't it? Great simplifications are in store for us. … It seems to me that only now that is American linguistics becoming really interesting, at least in its ethnological bearings.