The primary purposes of this study were to investigate the phonetic bases of nonstandard spellings invented by preschool and primary-grade children, to devise appropriate experimental techniques for eliciting judgments of phonetic relationships from young children, to identify the specific characteristics that influence children's categorization of speech sounds, and to identify the significance of children's phonetic judgments for phonetic classification and for the teaching of literacy. The six chapters of the book discuss such topics as invented spelling, experimental studies of clusters, experimental studies of preconsonantal nasals, and studies of vowels. Some of the major conclusions reached in this study are that (1) the basis for certain common nonstandard spellings is that children categorize speech sounds in unexpected but phonetically justified ways; and (2) categorization of speech sounds is an important component of early language learning because it influences children's efforts in spelling, giving rise to certain types of apparent errors which teachers should understand in order to respond appropriately. (TS)