This study in 1969-70 investigated morphological proficiency in relation to race, intelligence, and sex in a lower class rural kindergarten population in Florida. Subjects (145), Negro and white, male and female, were grouped in terms of high-, middle-, or low-intelligence using raw scores on a portion of the Kuhlmann-Anderson Intelligence Test. The subjects were then individually administered a 20-item adapted version of the Berko Morphology Test, with responses taped and transcribed in writing. Analysis of data included item and factor analysis of the adapted Berko Test, Multiple linear regression analysis, and non-statistical content analysis of test responses. Results of this study in a population controlled for socio-economic level, geographic distribution, and age-grade level showed a significant relationship between morphological proficiency and intelligence and race. No significant relationship between language proficiency and sex was found. Implications suggest the need for additional refined test instruments for intelligence and language, appropriate for use with lower class rural, southern subjects, as well as a need for a descriptive linguistic study of adult speech in the rural south. (Author/FWB)