Language was just that thing that happened when you opened your mouth at the table, squeezed a few noises out of your vocal chords, and induced Socrates thereby to pass the salt.

Astronomy is not the science of all objects with mass and weight and velocity. The objects it describes do not include '56 Chevies. Biology is not the science of all objects that consume and excrete and have inherited characteristics. The objects it describes do not include '56 Chevies. Linguistics is not the study of all possible symbols or symbol systems. The objects it describes do not include '56 Chevies.