The subject matter of the paper is an analysis of the semantic relations between sentence negation, performative negation, and declarations in reference to utterances which speech acts theory gives the label of representatives. Apart from linguistic-semantic analyses, empirical studies have been conducted on the manner in which sentence negation and performative negation are processed. The results of Study I demonstrate that the semantic relation between sentence negation and performative negation changes depend on the type of comment (positive vs. negative), and contextual factors (type of expectations towards events being commented on). As it turned out, when the situational context suggests a negative comment by the sender, participants offer similar interpretations of utterances with sentence negation and performative negation. In Study II the participants assessed the likelihood of the occurrence of the facts spoken of by a sender who uses sentence negation or performative negation. In a context suggesting positive utterances by the sender, a clear difference emerged between sentence negation and performative negation. This difference was not present in respect of negative expectations. The results achieved confirm the assumptions of the model of conversational inference regarding the influence of context on interpretation of a message. The recorded results indicate the semantic relations between declarations, sentence negation, and performative negation, which change depending on the affective significance of the message and contextual factors.