The purpose of the project described in this thesis was to provide high school students suffering from severe dialect interference problems with the skills to proofread their writing for S inflection errors, and to improve their grasp of the spoken idiom so that they could develop an ear for correct form. Subjects were two ninth-grade sections of LEX (Language EXperience) English (a literacy program for students reading five or more years below grade level). An instructional design system consisting of five stages (analysis, design, development, implementation, and evaluation) was used. The project was implemented in 5 sequenced lessons, each lasting 42 minutes, which combined class activity and individual work. Instructional material was designed to progress through visual discrimination and aural discrimination to proofreading in order to correct/supply inflections for nouns and verbs. Results showed that students scored an average of 18.26 (out of 20 points) on the posttest, for a gain score of 80%. Results indicated that students enjoyed participating and expressed a desire to continue. Results further showed that students who were originally passive became more approachable and more outspoken, and that students who were never competitive about school work discovered that success was real and attainable. (Twelve tables of data are included; 14 appendixes of tests, lessons, and surveys, and a list of 16 references are attached.) (PRA)