Phonology is the study of the mental representations of the sound units of language and the rules that govern how mental phonemes are realized in various contexts.
Phonology is also concerned with metrical and syllable structure.

Research in phonology at Penn covers a wide range of topics and perspectives with an emphasis on the detailed analysis of individual languages to inform the development of theoretical models.

Eugene Buckley has a special interest in the formal analysis of metrical phonology and related prosodic structure; he has worked for many years on this question in light of the complex stress system of Kashaya, a Pomoan language of northern California, and more recently has studied the stress patterns of the entire Pomoan family. (Currently he is completing a comprehensive dictionary of Kashaya, based mainly on materials collected by Robert Oswalt.) Buckley also has a long-standing interest in the role of explanation in phonological theory, namely the extent to which generalizations attributable to historical change, acquisition, and perception should be excluded from formal theories. In addition, he has explored the role of morphological information in phonological processes and implications for the organization of the grammar. Finally, many years of teaching a course on writing systems has enhanced his interest in the relation of written language to linguistic structure.

Rolf Noyer's work spans phonology and morphology. His phonological work is concentrated in two somewhat different areas. On the one hand, he studies metrical structure, including poetic meter and its basis in phonology; much of his recent work in this area has focused on Old French poetry, including Anglo-Norman poetry written in a curious type of "expanded" meter. On the other hand, he continues to investigate accent, tone, and their interaction in languages with pitch accent, especially Huave and Ancient Greek. His dissertation was one of the first full expositions of Distributed Morphology, a new theory of the architecture of morphosyntax which is still developing rapidly; he continues to work and publish in this frontier area of our field.

In addition, Mark Liberman has done work at the interface of phonetics and phonology, especially with regard to prosody, tone, and intonation. The program encourages students to apply formal models of phonology to such domains as historical-comparative linguistics; variation and change in progess; and interfaces with morphology, syntax, and pragmatics.

Coursework is built on the year-long introduction, Ling 530-531, taught by Noyer and Buckley to emphasize data analysis in both derivational and constraint-based approaches. Subsequent training is provided in Ling 603, the Topics in Phonology seminar; each semester, a different area is covered. Recent topics include: Non-Categorical Phonology; Generative Metrics; Prosodic Categories; Indo-European Accentology; Theoretical Alternatives; Distinctive Feature Theory.