Theoretical Phonology
Authors: de Lacy Paul 
Published: May 2016

Phonology has both a taxonomic/descriptive and cognitive meaning. In the taxonomic/descriptive context, it refers to speech sound systems. As a cognitive term, it refers to a part of the brain’s ability to produce and perceive speech sounds. This article focuses on research in the cognitive domain.

The brain does not simply record speech sounds and “play them back.” It abstracts over speech sounds, and transforms the abstractions in nontrivial ways. Phonological cognition is about what those abstractions are, and how they are transformed in perception and production.

There are many theories about phonological cognition. Some theories see it as the result of domain-general mechanisms, such as analogy over a Lexicon. Other theories locate it in an encapsulated module that is genetically specified, and has innate propositional content. In production, this module takes as its input phonological material from a Lexicon, and refers to syntactic and morphological structure in producing an output, which involves nontrivial transformation. In some theories, the output is instructions for articulator movement, which result in speech sounds; in other theories, the output goes to the Phonetic module. In perception, a continuous acoustic signal is mapped onto a phonetic representation, which is then mapped onto underlying forms via the Phonological module, which are then matched to lexical entries.

Exactly which empirical phenomena phonological cognition is responsible for depends on the theory. At one extreme, it accounts for all human speech sound patterns and realization. At the other extreme, it is little more than a way of abstracting over speech sounds. In the most popular Generative conception, it explains some sound patterns, with other modules (e.g., the Lexicon and Phonetic module) accounting for others. There are many types of patterns, with names such as “assimilation,” “deletion,” and “neutralization”—a great deal of phonological research focuses on determining which patterns there are, which aspects are universal and which are language-particular, and whether/how phonological cognition is responsible for them.

Phonological computation connects with other cognitive structures. In the Generative T-model, the phonological module’s input includes morphs of Lexical items along with at least some morphological and syntactic structure; the output is sent to either a Phonetic module, or directly to the neuro-motor interface, resulting in articulator movement. However, other theories propose that these modules’ computation proceeds in parallel, and that there is bidirectional communication between them.

The study of phonological cognition is a young science, so many fundamental questions remain to be answered. There are currently many different theories, and theoretical diversity over the past few decades has increased rather than consolidated. In addition, new research methods have been developed and older ones have been refined, providing novel sources of evidence. Consequently, phonological research is both lively and challenging, and is likely to remain that way for some time to come.