The study of phonological development has important implications for the diagnosis, understanding, and treatment of developmental language disorders. It also has implications for the understanding of language patterns in stuttering, disfluency, aphasia, bilingualism, second language learning, and dementia. Recent computational advances now make it possible for researchers to link high quality digital recordings to phonological and phonetic transcriptions. Using standards such as Unicode, IPA, and XML, the CHILDES database project now provides universal Internet access to large corpora of transcripts linked to audio for students of both first and second language acquisition, along with a wide array of tools for lexical, syntactic, and discourse analysis. However, the CHILDES Project has not provided effective tools for phonological and phonetic analysis. PhonBank seeks to bridge this gap by providing a new database on phonological development with transcripts linked directly to audio records. It also provides a program that automates creation and analysis of these new corpora. The construction of this database is being be supported by a group of 60 researchers and their students who have agreed to contribute already collected and transcribed corpora from children learning 17 different languages. Subjects include bilingual children, normally-developing monolinguals, and children with language disorders. The data are being structured to facilitate testing of models regarding babbling universals, variant paths in segmental and prosodic development, markedness effects, prosodic context effects, segmentation patterns, statistical learning, frequency effects, interlanguage transfer, diagnosis of disability, stuttering patterns, disfluency patterns, and the effects of morphology and syntax.