The language of the deaf has only recently become an area of concern for linguists. Of special interest are questions of the systematicity of deaf speech (is it systematic or idiosyncratic and none-rule-governed?) and the nature of its deviation from the speech of hearing people. The study presented here is an effort on the part of linguists, first of all, to analyze one aspect of the language, the phonology, of a deaf child, and secondly, to propose a method for improving the speech of the child based on knowledge of normal patterns of phonology acquisition. An analysis of the phonology of Emma, a profoundly deaf English child (age 11;9) is presented in this paper, and it is demonstrated that the child's speech is indeed systematic and rule-governed, though the system is by no means that of standard English. The ways is which Emma's speech deviates from the standard are also examined, comparing her patterns with universal and English patterns. Finally, a proposal for therapy is made based on facts of normal phonology acquisition and the notion that deaf speech is, in fact, systematic. (Author/NCR)