The double negative in English dats back to the ancient time of proto-indoeuropean language where it was a current way of expression. So in fact it is an archaism, the way it was originally, although a little bit differently than in today's slavic languages. Originally, double negation was allowed only if the negated verb preceeded the negative pronoun/adverb/whatever, but not vice versa (when the negative pronoun preceded the verb, the verb itself was not negated). This priciple functions in Ancient Greek: úk'oida údena (I haven't seen) (no one) = "I haven't seen anyone"/"I have seen no one" x údena oida (no one) (I have seen) = "I haven't seen anyone"/"I have seen no one" If the verb in the second phrase is negated, the meaning is reversed: údena úk'oida (no one) (I haven't seen) = "I haven't seen *no one*"/"I did actually see someone" Just like in today's English, but only with proper intonation... there has to be an accent on "no one" in order to consider it to be negated negation and not simply bad grammar. In Czech, the negation is always double without relation to the word order (if there is not double negation, the meaning is different).