Some comments on T-unit research

Abstract This article reviews the research on the use of the T-unit as a measure of language ability. Though there is much evidence of the value of the T-unit in the case of first language, the article demonstrates that the measure has limited utility in the case of second language. The primary reason for this lies in the very nature of the T-unit—the fact that it bases itself solely on syntax. Thus, on the one hand the T-unit fails to deal adequately with second language learners' morphological errors, which are of a type and frequency that differ from those of the first language. On the other hand, the measure does not reward learners for sophistication in areas such as vocabulary. Further, the theoretical construct upon which the T-unit is based is still quite nebulous and efforts to show why and how the measure should work have not been successful.