The DO NOT seems to me, to be a double negative, and should cancel itself out to leave - I speak Swedish! I don't see how you think there is a double negative there. In standard English all negative forms except primary BE and, for a small number of speakers, primary HAVE, have an auxiliary verb (or more than one) and not.
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AnonymousI do not speak Swedish.The DO NOT seems to me, to be a double negative, and should cancel itself out to leave - I speak Swedish!I don't see how you think there is a double negative there.