The proposed research studies children's knowledge of the sound structure of their language, and how this knowledge is reflected in their learning of reading and spelling. An improved understanding of the knowledge and expectations that children bring with them when they learn to read and write should shed light on some of the difficulties that they face and how these difficulties might be overcome. Two specific lines of research are proposed. The first line of research concerns syllable structure. The units into which children divide spoken syllables are studied, using as a basis linguistic theories of syllable structure. Also investigated are effects of syllable structure on children's performance in prereading tasks, reading, and spelling. The second line of research concerns the possibility that some children attend to phonetic details to which many adults are insensitive. Thus, children may produce unconventional but phonetically plausible spellings. Both experimental and naturalistic methods will be used. The experimental studies involve children from kindergarten to fifth grades, as well as college students. Tasks involving spoken and written words are used. In addition, a large corpus of first graders' spontaneous spellings is analyzed to discover the spelling-sound relationships that the children employ. The results of this research should help us to understand some of the difficulties that children encounter in learning how to read and spell.