This paper claims that language use ought to be considered dynamically, and that interlocutors' effort and utility has to be assessed jointly, against the effect postulated by the communicative goal in a certain speech community. It presents the Neo-economy Principle that every operative utterance is the outcome of the interlocutors’ exertions to seek after the best equilibrium of the cost and utility in their verbal communication. This optimal equilibrium is controlled by five maxims: the Maxims of Proximal Choice, of Common Presuppositions, of Conformity, of General Equilibrium, and of Utterance Utility, which serve as a guide to a fortunate communication act. It is expected that such a theory may better explain speech acts from the economy view.