T Unit and Linguistics

Measuring T Units

William Faulkner
William Faulkner.


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A T-Unit is a measurement in linguistics, and refers to a main clause plus any subordinate clauses that may be attached to it. As defined by Kellogg W. Hunt (1964), the T-unit, or minimal terminable unit of language, was intended to measure the smallest word group that could be considered a grammatical sentence, regardless of how it was punctuated. Research suggests that the length of a T-unit may be used as an index of syntactic complexity. In the 1970s, the T-unit became an important unit of measurement in sentence-combining research.

T Unit Analysis

  • "T-unit analysis, developed by Hunt (1964) has been used extensively to measure the overall syntactic complexity of both speech and writing samples (Gaies, 1980). The T-unit is defined as consisting of a main clause plus all subordinate clauses and nonclausal structures that are attached to or embedded in it (Hunt, 1964). Hunt claims that the length of a T-unit is parallel to the cognitive development of a child and thus the T-unit analysis provides an intuitively satisfying and stable index of language development. The T-unit's popularity is due to the fact that it is a global measure of linguistic development external to any particular set of data and allows for meaningful comparison between first and second language acquisition. . . .
  • "T-unit analysis has been successfully used by Larsen-Freeman & Strom (1977) and Perkins (1980) as an objective measure to evaluate the quality of ESL student writing. T-unit measures used in this study include words per composition, sentences per composition, T-units per composition, error-free T-units per composition, words in error-free T-units per composition, T-unit length, and ratio of errors versus T-units per composition." (Anam Govardhan, "Indian Versus American Students' Writing in English." Dialects, Englishes, Creoles, and Education, ed. by Shondel J. Nero. Lawrence Erlbaum, 2006)
  • "By analogy with the way modifiers work in sentences, [Francis] Christensen thinks of subordinate T-units as modifying the more general T-unit that semantically encompasses them. The point can be illustrated by the following sentence of William Faulkner's:
Joad's lips stretched tight over his long teeth a moment, and he licked his lips, like a dog, two licks, one in each direction from the middle.
  • 'Like a dog' modifies 'licked his lips,' a relatively general description which could encompass various other types of lip-licking. Similarly, 'two licks' starts to explain how a dog licks its lips, hence is more specific than 'like a dog.' And 'one in each direction from the middle' explains 'two licks' even more specifically." (Richard M. Coe, Toward a Grammar of Passages. Southern Illinois Univ. Press, 1988)

T-Units and Ordered Development

  • "Since young children tend to connect short main clauses with 'and,' they tend to use relatively few words/T-unit. But as they mature, they begin to use a range of appositives, prepositional phrases, and dependent clauses that increase the number of words/T-unit. In subsequent work, Hunt (1977) demonstrated that there is a developmental order in which students develop the capacity to perform types of embedding. Other researchers (e.g. O'Donnell, Griffin & Norris, 1967) used Hunt's unit of measurement to conclusively show that the words/T-unit ratio went up in both oral and written discourse as writers matured." (Thomas Newkirk, "The Learner Develops: The High School Years." Handbook of Research on Teaching the English Language Arts, 2nd ed., ed. by James Flood et al. Lawrence Erlbaum, 2003)