Negation in Northwest Gbaya

In Northwest Gbaya there is a single dedicated negative marker ná which is
reconstructed in Proto-Gbaya. It is placed after the verb, in the very last position of the
verb phrase. For standard negation, negative verbal constructions are symmetric in
realis mood, as the negator is simply added with no changes, but there is a
paradigmatic asymmetry as perfective forms are blocked in the negative. The paradigm of
the imperfective forms is narrowed to three forms. In the virtual mood, both
perfective and imperfective forms carry the negator, but these paradigms are narrowed
to the two neutral forms. Attributive verbal predication can be negated but this
is not frequent. In the command mood, the construction is the same as in Realis
mood, but there are two new forms dedicated to negative commands (vetitive and
prohibitive). All non-verbal predications (identificational, locative, existential and
presentative) add the potential verb be ‘can be’ when negated. This potential verb
carries the negator which is placed clause-finally. Finally, there is a constituent
negator to negate any element except a predicate.