Production of tense markers in C-VIC, a computerized visual communication system, was utilized as a treatment for three patients with severe expressive aphasia. Patients practiced constructing C-VIC tense marked sentences and then producing English equivalents. After training, all patients demonstrated significant improvements in English verb retrieval and production of correct tense morphology. Generalization of morphological rules for past tense production was seen for regular, but not irregular verbs. These results support the LaPointe and Dell (1989) extension of the Garrett (1975, 1992) model specifying a search through so-called verb phrase notion stores as a process mediating transition from functional to positional levels, but also suggest an additional constraint on the output of the verb notion store search.