malachai wrote: "irregardless" and "I could care less" are not grammatically inoperative either. They make sense for the people who use them. The fact that they are in widespread use means they that do make sense.
In Hamlet's words, "Ay, [madam,] it is common." The subtext here is that common
is not always desirable. Stupidity when driving is also in widespread use...therefore...
"When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means just what I choose it to mean -- neither more nor less."
"The question is," said Alice, "whether you can make words mean so many different things."
"The question is," said Humpty Dumpty, "which is to be master--that's all."
Which attitude should carry the day? Yes, language evolves with usage (words such as silly and nice immediately spring to mind). But, does this mean change must be determined by the lowest common denominator? If that is the case, then why bother with piffles such as grammar, composition and literature classes?
Communication which which fails to deliver its message is pointless. Carelessness and ignorance are not the foundations of any
achievement in human history; why champion tossing clear thought and its clear expression to the scrap heap because it's more convenient for carelessness or ignorance?
sluggo! you beat me to the "jumping off the cliff" metaphor.