A method and system for adapting computer-based personalities, as manifested by textual or audio communications, is disclosed. The communications comprise one or more phrases that may be selected non-deterministically. The frequency distribution of the plurality of potential phrases is updated based on the behaviors of the communications recipients. Thus, the frequency of the selection of phrases included in communications, and hence the “personality,” of the computer-based system, is influenced by prior usage behaviors. The computer-based personality may also exhibit “self-awareness” by monitoring changes in phrase frequency distributions over time, as well as being capable of expressing awareness of, and inferences from, changes in the behavior patterns of users over time.