Verbal Behavior by B.F. Skinner, represents a systematic extrapolation of the concepts and principles of operant conditioning to account for language as behavior. I examine the logic and conceptual deficiencies of Skinner’s formulation, based upon the analysis of a limited number of problems: a) the definition of verbal behavior, b) the selection of the ‘word’ as the dominant unit of analysis, c) the morphological nature of the taxonomy of verbal behavior, d) the lack of systematicness of such classification, e) the establishment of discriminated verbal operants, and f) the logical and functional distinction between the mand, the tact, and the intraverbal. It is stressed the importance of theoretical and conceptual analyses for scientific progress.