The other day, I was talking to someone and he said nonchalantly "Irregardless, I could care less." I let the statement go in passing because I knew what he was trying to say. But really, if you think about it... I don't think he said what he meant to say. First of all, what does "irregardless" mean? I mean, I know what regardless means and so "irregardless" should mean the opposite; meaning: Regard; to have an interest in something. Regardless; to have no interest in something or having very little to do with. So "irregardless" should mean (as in a double-negative), to NOT have very little to do with or consideration for. But this was just the beginning of his contradictory statement. It then followed that he could care less. That is, he could indeed be less interested and that this thing that he was talking about actually did matter to him despite the variables previously mentioned! So really, he meant to say, "Irrespective to any condition, this just doesn't matter to me." However, what he did say, translated accurately and logically was, "Depending on the circumstance, I could take this very seriously... but maybe not."
There really is no word "irregardless" and I believe that most people really mean that they "couldn't care less" when they say they "could care less."