Friday is for rhetoric! Why all the fuss about using a language correctly? As long as you can understand me, shouldn’t I be able to express ideas however I want? For that matter, why don’t you just learn to understand whatever I mean however I say it? Quintilian points out some very valid reasons for standard usage in writing and speaking. There’s an art to speaking well.
Quintilian, and J.S. Watson. Institutes of Oratory. Edited by Lee Honeycutt, 2010. Kindle Electronic Edition. Book I Chapter 6
Language usage matters, in speaking as in writing. It is important that a speaker find and respect the guidance of appropriate usage. Quintilian says, “What it requires is that a writer or speaker should compare whatever is at all doubtful with something similar concerning which there is no doubt, so as to prove the uncertain by the certain” (I.6.4). This is especially a critical feature in the heavily inflected languages. His examples mostly have to do with bringing Greek ideas into Latin. The rhythm, likewise, of words in Latin is very important, in pronunciation if not also for arrangement of words in a sentence. Quintilian spends several paragraphs arguing that by analogy one might find forms of words which are correct but not supported by common usage. He seems eager to find that correct form because language will follow coherent patterns. Yet those rules, he observes, (I.6.16) may not have been followed, but could merely be extrapolated. Creating words which would be theoretically correct is merely annoying. “It appears to me, therefore, to have been not unhappily remarked that it is one thing to speak Latin and another to speak grammar” (I.6.27).
Quintilian then turns his attention to etymology. He views it as a weak practice to try to make many relationships by rearranging words, adding or subtracting syllables and the like. Rather than forcing oneself to use a specialized vocabulary which may seem stilted, “as the oldest of new words will be the best, so the newest of old words will be the best” (I.6.41).