Abstract: It is claimed by Horn that the negative operator ‘not’ is ambiguous since its metalinguistic use, distinguished from descriptive truth-functional negation which operates over a proposition, has been characterized as non-truth-functional.We have investigated four languages which are claimed to have special markers of metalinguistic negation, and found them nothing but markers of ordinary pragmatic functions, such as focus markers, metarepresentation markers, contrastive markers, etc., which means Horn’s point of pragmatic ambiguity can not stand close scrutiny.