Dear all,

this questions is mainly directed at English linguists; more precisely: L2 syntactic complexity researchers. I know some are registered here, so I'm hoping to grab their attention.

I'm currently writing a discussion of the T-unit in L2 syntactic complexity measures. As you know, the T-unit is "a main clause and all its subordinate clauses attached to it". It was introduced by Hunt (1965) for measuring written L1 development, but has since been extended to Second Language Acquisition and L2 development research.

Hunt (1965) defined the clause as any structure that has "a subject and a finite verb". This specifically excludes subjectless clauses as well as clauses headed by a verb phrase with a non-finite verb.

My question is: Why is the clause commonly defined as "subject + verb_finite" in T-unit-based research? Can anyone point me to critical discussions of this and why non-finite verb phrases do not form clauses in this definition?

I am already aware of some of the seminal publications which contain such discussions (e.g. Wolfe-Quintero et al. 1998), but please feel free to list anything that comes to mind.

To already give it away: My definition of clause follows that of most of the reference grammars (Biber et al. 1999, Quirk et al. 1985), which include non-finite clauses.

Thank you in advance!