Literature suggests that illiterate subjects are unaware of the phonological structure of language. This fact may influence the characteristics of aphasic speech, namely the structure of paraphasias. A battery of tests was developed for this study to be used with aphasic subjects (literate and illiterate), in order to explore this topic in more detail. This article aims to present the experimental design and the results of this test battery composed of two sub-tests: (i) a naming test with words that belong to three distinct groups: high frequency simple words (HFSW), low frequency simple words (LFSW), and low frequency complex words (LFCW); and (ii) a word repetition test. The variables of literacy, frequency and word morphology, and their effect on the performance of aphasic groups, were correlated in this study. Morphology was the variable that exercised the greatest influence on the verbal production of the participants. (Contains 8 figures, 8 tables and 1 note.)