About

William Idsardi is a professor in the Department of Linguistics and a member of the Maryland Language Science Center, with additional affiliations in the Program in Neuroscience and Cognitive Science. His research expertise encompasses neurolinguistics, phonology, and psycholinguistics. Idsardi's work focuses on the mental models of speech events in time, exploring how phonological features and events are represented and ordered in the brain. He has contributed to understanding underspecification in phonology, the role of phonemes in lexical access, and the neural basis of speech perception, including categorical effects in fricative perception. His research also investigates computational phonology, language acquisition, and the differences in learning mechanisms between phonology and syntax. Idsardi's contributions include defending the central role of phonemes in phonological theory and developing models for phonological category acquisition, such as Bayesian models for Inuktitut vowels. His work integrates linguistic theory, cognitive science, and neuroimaging techniques to advance understanding of language processing and acquisition.

Research topics

• Computer Science
• Artificial Intelligence
• Linguistics
• Cognitive psychology
• Psychology
• Neuroscience
• Developmental psychology
• Biology
• Cognitive science
• Philosophy

Selected publications

• Sentence and Word Complexity

  2026-01-07

  book-chapterSenior author
  PublisherDOI

• Integrated versus independent processing of auditory features in speech sounds

  Language Cognition and Neuroscience · 2026-03-04

  articleSenior author
  PublisherDOI

• Evoked category representations

  2025-04-21

  preprintOpen accessSenior author

  A critical part of the Mismatch Negativity (MMN) mechanism is the construction of a memory trace encoding regularities extracted from the stimuli in an oddball paradigm. In an influential study, Phillips et al. (2000) argued that varying phonetic standards within the limits of a phoneme category prompts the auditory cortex to access representations of the “discrete phonological categories” (p. 1050), resulting in a mismatch response by comparing the deviant stimulus to an abstract, evoked category representation. The present study tested the strongest interpretation of this claim–namely, that the phoneme itself is retrieved from long-term memory and serves as the memory trace for the stimulus sequence. This interpretation has been the implicit, if not explicit, basis for a body of research employing the varying-standards paradigm to probe phonological underspecification. However, while previous research has focused on contrasts between distinct phonemes, we examined a previously untested prediction of this interpretation: that varying the standards should eliminate the MMN when the contrast is within a single phoneme category. Contrary to this prediction, we observed a mismatch negativity to a within-category deviant even when standards were varied. In two additional experiments we further examined whether the within-category MMN is from long-term memory representations of phonetic realizations of the phoneme, or from listeners constructing ad hoc statistical representations of the stimulus distribution. The weight of the evidence suggests that the within-category MMN observed with varying standards reflects sensitivity to the statistical structure of the stimuli, rather than activation of abstract phonological categories.

  PublisherOA PDFDOI

• Perception of sequential structure in budgerigar (<i>Melopsittacus undulatus</i>) warble song

  The Journal of the Acoustical Society of America · 2025-10-01 · 1 citations

  article

  Whether the sequential structure of bird song has perceptual significance has long been an interest of animal behaviorists. The long, rambling warble song of male budgerigars is acoustically complex and composed of a number of distinct elements uttered in streams lasting several minutes, usually accompanied by various courtship behaviors, such as head bobbing and beak touching. Recent work has shown that warble song may have a sequential structure, or patterned repetition of elements. This raises questions as to whether budgerigars can detect changes in natural warble streams and to what extent these capabilities are specific to conspecific song. Here, this study examined the perception of long bouts of warble song from male budgerigars. Using operant conditioning and a psychophysical procedure, the study probed the limits of the birds' ability to detect various changes in new and familiar sequences of warble elements. The study shows that budgerigars can detect sequence changes in short unfamiliar sequences of warble and in much longer segments of familiar warble sequences.

  PublisherDOI

• A neural architecture for selective attention to speech features

  2023-08-14 · 2 citations

  article
  PublisherDOI

• Speech features are weighted by selective attention

  2023-01-01 · 1 citations

  articleOpen access
  PublisherDOI

• We don’t know how the brain stores anything, let alone words

  Trends in Cognitive Sciences · 2022 · 27 citations

  Senior authorCorresponding
  • Psychology
  • Cognitive science
  • Cognitive psychology
  PublisherDOI

• Underspecification in time

  The Canadian Journal of Linguistics / La revue canadienne de linguistique · 2022-12-01 · 7 citations

  articleOpen access1st authorCorresponding

  Abstract Substance-free phonology or SFP (Reiss 2017) has renewed interest in the question of abstraction in phonology. Perhaps the most common form of abstraction through the absence of substance is underspecification, where some aspects of speech lack representation in memorized representations, within the phonology or in the phonetic implementation (Archangeli 1988, Keating 1988, Lahiri and Reetz 2010 among many others). The fundamental basis for phonology is argued to be a mental model of speech events in time, following Raimy (2000) and Papillon (2020). Each event can have properties (one-place predicates that are true of the event), which include the usual phonological features, and also structural entities for extended events like moras and syllables. Features can be bound together in an event, yielding segment-like properties. Pairs of events can be ordered in time by the temporal logic precedence relation represented by ‘&lt;’. Events, features and precedence form a directed multigraph structure with edges in the graph interpreted as “maybe next”. Some infant bimodal speech perception results are examined using this framework, arguing for underspecification in time in the developing phonological representations.

  PublisherOA PDFDOI

• Comment on “Nonadjacent dependency processing in monkeys, apes, and humans”

  Science Advances · 2021 · 8 citations

  • Computer Science
  • Computer Science
  • Neuroscience

  and caution against their conclusion that the behavioral evidence in their experiments points to nonhuman animals' ability to learn syntactic dependencies, because their results are also consistent with the learning of phonological dependencies in human languages.

  PublisherDOI

• Social Inference May Guide Early Lexical Learning

  Frontiers in Psychology · 2021 · 11 citations

  Senior authorCorresponding
  • Artificial Intelligence
  • Psychology
  • Computer Science

  We incorporate social reasoning about groups of informants into a model of word learning, and show that the model accounts for infant looking behavior in tasks of both word learning and recognition. Simulation 1 models an experiment where 16-month-old infants saw familiar objects labeled either correctly or incorrectly, by either adults or audio talkers. Simulation 2 reinterprets puzzling data from the Switch task, an audiovisual habituation procedure wherein infants are tested on familiarized associations between novel objects and labels. Eight-month-olds outperform 14-month-olds on the Switch task when required to distinguish labels that are minimal pairs (e.g., "buk" and "puk"), but 14-month-olds' performance is improved by habituation stimuli featuring multiple talkers. Our modeling results support the hypothesis that beliefs about knowledgeability and group membership guide infant looking behavior in both tasks. These results show that social and linguistic development interact in non-trivial ways, and that social categorization findings in developmental psychology could have substantial implications for understanding linguistic development in realistic settings where talkers vary according to observable features correlated with social groupings, including linguistic, ethnic, and gendered groups.

  PublisherOA PDFDOI

Recent grants

• Doctoral Dissertation Research: Categorization and Segmentation Inside and Outside Language

  NSF · $18k · 2017–2018

Frequent coauthors

• Haifa Sandler

  Sussex County Community College

  464 shared

• Huang Harvard

  Sussex County Community College

  464 shared

• C.-T James

  464 shared

• Jonathan David

  Defence Science and Technology Laboratory

  464 shared

• Kersti Börjars

  University of Oxford

  464 shared

• S. T. Hannahs

  Florida State University

  464 shared

• Koontz-Garboden Manchester

  University of Manchester

  464 shared

• Clark Middlesex

  Newcastle University

  464 shared

Labs

• CLIPPI

Education

• PhD, Linguistics and Philosophy

  Massachusetts Institute of Technology

  1992

• BA

  University of Toronto

  1988