The contribution of inter-behavioral psychology to the study of the written language is analyzed. Structured in three sections: 1. An overview of the contributions to Spanish language teaching and evaluation in the Mexican primary school during 10-year-period studies, as well as an analysis of the effectiveness of the written language mastery and acquisition of its technological derivations, with the support of a Spanish textbook and its adaptation to Yaqui language. 2. A discussion of data derived from an intervention program for the development of texts production competences, through three functional separations. 3. A proposal for planning linguistic competences and material in Spanish language for fifth grade of Primary School, according the new educational reforms, approaching its morphologic and function configuration.