T Unit Measurement in Linguistics

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-units 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 composi tion, 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 Faulkners: Joads 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. ODonnell, Griffin Norris, 1967) used Hunts 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)