This volume is a collection of advanced laboratory phonology research papers concerned with the interaction between the physical and the mental aspects of speech and language. The traditional linguistic theoretic distinction between phonetics and phonology is put to the test here in a series of articles that deal with some of the fundamental issues in the field, from first and second language acquisition to segmental and supra-segmental phenomena in a range of different languages. Unique features of this volume are the development of innovative experimental methodologies, advanced techniques of data analysis, latest-generation equipment for the observation of speech, and their combined critical application to the study of the phonetics-phonology interface.