> Or maybe—and this is the theory I like best, but can least substantiate—“No, totally” is really a contraction of “I know, totally.” That is linguistically improbable; I know of no instance in the English language where a homophonic slippage of this sort has taken place. But I like the theory anyway, because it captures what is often the semantic intent of “No, totally” with uncanny precision: I understand, and I am fully in accord.