Theory that analyzes negation in terms of a special kind of linguistic activity, negating or denying; so that to say, for example, 'It's not raining' may indeed be (as anyone would agree in straightforward cases) to deny that it is raining, but is also to utter a sentence which gets its meaning from that very fact.
The alternative view would say one can only deny something by using a sentence that has its meaning independently of any act of denial.
The German logician Gottlob Frege (1848-1925) raised an objection, relevant to other speech act theories too, about what happens when 'not' occurs in a clause governed by a phrase like 'if or 'I wonder whether'.
He also asked whether utterances such as 'Christ is immortal' count as assertions or denials.
G Frege, 'Negation', Translations from the Philosophical Writings of Gottlob Frege, P T Geach and M Black, eds (1952)