Empirical ACL semantics also takes an essentially pragmatic point of view, and allows for a "saying = acting"-based interpretation of messages. But in contrast to speech act theory, the meaning of an utterance is here entirely in its expectable behavioral consequences, moving empirical semantics close to Wittgenstein's concept of language games and also close to philosophical pragmatism. This consequentialist perspective does not mean to neglect "saying = acting", since despite being basically an a-posteriory approach, it allows for modeling immediate performance of acts in saying something due to the fact that it can learn the expectable consequences of a certain type of utterance, and apply what it has learned immediately at the time a new utterance of the same type occurs. In terms of Austin's original speech act theory, we could say that empirical semantics is able to learn conventions in form of expectations.
Empirical-rational semantics refines the very general approach of empirical semantics by explicitely considering the intentions of a rational speaker. But again, such "intentions" are only considered in form of specific behavioral consequences, arising from observable, ostensible intentions only. Instead of distinguishing illocution and perlocution as speech act theory does, it treats the alleged intentions of the speaker as a special case of the actual consequences of his respective utterances. Namely, the alleged intention causes the (expectable) speaker's behavior of supporting the alleged goal which has been expressed by means of the utterance. The notion of alleged intentionality is cleanly separated from "real" (mental) intentionality - a sincerity condition for the performance of communication acts do not exist in empirical(-rational) semantics.
More information on speech act theory can be found here. An in-depth criticism of speech act theory can be found here.