As instances of behavior, words interact with environments. But they also interact with each other and with other kinds of behavior. Because of the interlocking nature of the contingencies into which words enter, their behavioral properties may become increasingly removed from nonverbal contingencies, and their relationship to those contingencies may become distorted by the social contingencies that maintain verbal behavior. Verbal behavior is an exceedingly efficient way in which one organism can change the behavior of another. All other functions of verbal behavior derive from this most basic function, sometimes called verbal governance. Functional verbal antecedents in verbal governance may be extended across time and space when individuals replicate the verbal behavior of others or their own verbal behavior. Differential contact with different verbal antecedents may follow from differential attention to verbal stimuli correlated with consequential events. Once in place, verbal behavior can be shaped by (usually social) consequences. Because these four verbal processes (verbal governance, replication, differential attention, and verbal shaping) share common stimulus and response terms, they produce interlocking contingencies in which extensive classes of behavior come to be dominated by verbal antecedents. Very different consequences follow from verbal behavior depending on whether it is anchored to environmental events, as in scientific verbal practices, or becomes independent of it, as in religious fundamentalism. (Contains 1 figure.)