Purdue University Graduate School
Final Dissertation David Crouch.pdf (1.91 MB)

Pre-Post Change in L2 Oral Fluency: the Lexico-Syntax of Large Fluency Gainers

Download (1.91 MB)
posted on 2020-04-27, 16:36 authored by David C CrouchDavid C Crouch

The theory underlying L2 oral fluency has focused on cognitive processes, particularly proceduralization (Anderson, 1983; Levelt, 1989, 1999) and linguistic constructs, especially vocabulary and grammar (Segalowitz, 2010). Towell, Hawkins, and Bazergui (1996) argued that development of formulaic language enables automatic speech production. However, no research has studied the longitudinal development of L2 oral fluency concurrently with any of the following lexical variables: lexical frequency profile, formulaic language use, and MTLD (a measure of lexical diversity). The purpose of the present study is to clarify the process by which L2 oral fluency, syntax, and vocabulary develop concurrently.

Data analysis involved three sequential phases: oral fluency analysis, lexico-syntactic analysis, and discourse analysis. Oral fluency measures were calculated using the transcribed oral test responses of 100 L1-Chinese EAP learners at the beginning and end of a required two-course EAP language and culture sequence at Purdue University. The task completed was a computer-administered, two-minute argumentative speaking task. This study included eight oral fluency measures: speech rate, mean length of speech run, articulation rate, phonation time ratio, mean length of silent pause, mean length of filled pause, silent pause frequency, and filled pause frequency. For the ten participants who made the largest percentage-wise oral fluency gains (in terms of the oral fluency variable associated with the largest effect size of gains), oral transcripts were analyzed to compute descriptive statistics for the three lexical variables mentioned above and three syntactic variables: coordinate clause ratio, dependent clause ratio, and words per T-unit.

Results indicated significant change in all oral fluency measures, except mean length of silent pause and mean length of filled pause. The largest gains were made in mean length of speech run. Of the linguistic variables, the largest longitudinal change was associated with coordinate clause ratio. Discourse analysis of the transcripts of large fluency gainers' pre-post responses suggested that large fluency gainers used coordinate clauses to build more sophisticated discourse models in the post-test response than they did in the pre-test response. Implications for L2 oral fluency theory, EAP pedagogy, and L2 oral assessment are discussed.


Degree Type

  • Doctor of Philosophy


  • English

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Dr. April Ginther

Additional Committee Member 2

Dr. Margie Berns

Additional Committee Member 3

Dr. Tony Silva

Additional Committee Member 4

Dr. Harris Bras

Usage metrics



    Ref. manager