Although past research suggests that the spatial diffusion of linguistic features across a landscape is a simple and clear-cut process, our research in Oklahoma suggests otherwise. We collected data for this study in a statewide, multifaceted investigation of grammatical, lexical, and phonological variation in Oklahoma and analyzed it using several cartographic and statistical procedures. Our purpose was to uncover some of the diffusion processes tied to language that are at work in Oklahoma. We used the General Linear Model (GLM), a multivariate statistical procedure, to identify barriers and amplifiers that influence the geographic distributions of linguistic features. The results suggest that linguistic diffusion in Oklahoma happens in a hierarchical pattern in some cases; in others, the spread is contra-hierarchical with innovations expanding up, rather than down, the urban hierarchy. A correlation of diffusion patterns with social factors that serve as barriers to, or amplifiers of, the diffusional process suggests that different patterns of diffusion may be tied to the different social meanings that linguistic features carry. In the data examined, those innovations that diffuse hierarchically represent the encroachment of external norms into an area, while those features that diffuse in a contra- hierarchical fashion represent the revitalization of traditional norms. ©1997 Oklahoma Academy of Science