Speechless

Why, nay How is that word ever spoken in a self-referential present tense manner -"I am speechless". In its very utterance, it contradicts itself. I dislike when people contradict themselves, but to do it so simply, and without concern to what they are saying is ridiculous. And for it to be a common phrase, that is just unacceptable, why not just say nothing, or "I'm not sure how to respond". At least that way you are not outright lying, and you get the same meaning.