If syntactic Negation, then the following factors are likely: a. moveability of Negation; b. prosodic independence (e.g. the Negation morpheme carries a stress of its own); c. in written language: orthographic separation; d. the Negation morpheme by itself carries inflectional affixes.
Standardized
IF negation is syntactic, THEN a. moveability of Negation; b. prosodic independence (e.g. the Negation morpheme carries a stress of its own); c. in written language: orthographic separation; d. the Negation morpheme by itself carries inflectional affixes.
Some of these truths are tautologies.