Redundancy and Deficiency

April 12-14, 2023 – University of Vienna


After 12 years, GLOW returns to Austria, and will have a topic for the main colloquium. GLOW 46 focuses on redundancy and deficiency in grammar. Although the concepts of deficiency, and especially redundancy, are very prominent in communication, information science, and functional approaches to grammar (see e.g., Wit & Gillette 1999), they have been less systematically studied from the perspective of formal approaches to grammar. The goal of this conference is to bring together researchers investigating various notions and applications of deficiency and redundancy in phonology, morphology, syntax, and semantics, as well as their relevance in language variation, change and acquisition. By considering a range of empirical and theoretical patterns and implementations of these concepts, we hope to establish common properties that will allow us to connect the well-studied extra-grammatical cognitive uses of deficiency and redundancy to grammar-internal mechanisms.

Deficiency has been used to generalize over various patterns in grammar, such as those where “an active element E is unable to inactivate a matched element by deleting its unvalued features, […] differing in some respect from otherwise identical active elements that induce deletion” (Chomsky 2001). Redundancy has been most  prominently discussed in information science and in functional approaches to language, where it is associated with robustness of information transfer. Shannon (1951) defines it as the “measure of the extent to which it is possible to compress [the message] if the best possible code is used,” a definition that also aligns with the usage in both structuralist and generative phonology. Bußmann (1998) speaks of  “excess information, that is, information expressed more than once and which hence could easily be forgone in some occurrences.” Lastly, Wit & Gillette (1999) provide a definition compatible with formal models of grammar, as it invokes internal systematicity and uses the notion of features, seeing redundancy as “the internal systematicity and rule governed behavior of a language in which two or more of its features serve the same function.” 

Linguistic derivations or computations are typically modeled as functions, i.e. mappings from an input to an output. Taking deficiency and redundancy as properties of these functions, i.e. of relations between the input and the output, they emerge as different directions of the same relation. When the input has content that is not realized in the output, then it involves redundancy, i.e. the output is deficient; and vice versa. It is hence possible to define redundancy as such a mismatch where an operation in grammar needs to ignore part of its input or output in order to apply properly, and deficiency as one where the operation needs to enrich its input or output, or to apply in a partial way. 

A diverse range of phenomena involve or can be described by relations of redundancy or deficiency, including but not restricted to: 

  • Syntax: atypical agreement patterns, doubling phenomena, deficiencies in feature specifications, and empty categories of various types 
  • Morphology: syncretism, defaults and elsewheres of various types, cumulative and extended exponence
  • Phonology: epenthesis, wobbly segments, various phonological phenomena modeled by underspecification, relinking or floating elements
  • Semantics: type lowering and lifting, pragmatic strengthening, presupposition canceling. 

Not only rules generalized in the analysis of empirical data, but also deeper underlying operations postulated by various frameworks can be examined in light of deficiency and redundancy; for instance, various types of the operation merge (internal vs. external, set vs. pair…). We invite papers assessing these and/or other foundational aspects of grammar from the perspective of the role played by redundancy and deficiency.

Contributions enriching our understanding of these phenomena and of grammar by analyzing or modeling them in terms of redundancy and deficiency are especially welcome for the main colloquium.


Bußmann, Hadumod. (1998). Routledge Dictionary of Language and Linguistics. 1. Publ. in Paperback. ed. Print. Routledge Reference. 

Chomsky, N. (2001). Derivation by Phase. In M. Kenstowicz (Ed.), Ken Hale: A Life in Language (pp. 1-52). Cambridge, MA: MIT Press.

Shannon, Claude E. (1951). The redundancy of English. In Cybernetics; Transactions of the 7th Conference. New York: Josiah Macy, Jr. Foundation.

Wit, E. C., and Marie Gillette.  (1999). What is linguistic redundancy? Technical report University of Chicago.