This paper distinguishes several ways in which phonemic information might be employed in spelling; examines some empirical data on the consequences of using these information sources; formulates hypotheses about the underlying processes involved; and suggests possible implications for the teaching (and learning) of spelling. Included are tables of the phoneme code with graphemic options and examples, Comparisons of Spelling by Elementary School Pupils with the Hanna-Rudorf Algorithm, and figures depicting the spelling and reading errors by means of a Generator-Test Process. The simulation technique discussed may be used to identify the spelling processes used by individual children and the information they hold in memory, and to diagnose and prescribe treatment for individual spelling problems. (Author/LS)