Chapter 2. Grammatical structures and oral fluency in immediate task repetition
Trigrams across repeated performances
In this study we examine to what extent words and grammatical structures are re-used when a speaking task is repeated with the same content (i.e., specific task repetition). We examine this re-use, which has been argued to support proceduralization and fluency development (N. de Jong & Perfetti, 2011), under both constant and increasing time pressure, and we investigate the correlation between re-use and fluency. The analyses are performed not only on individual words but also on trigrams, which are sequences of three words (e.g., the red car; here: lexical trigrams) or three parts of speech (e.g., det adj noun: POS trigrams), to capture grammatical structure. Thirty-nine adult ESL speakers completed repeated retellings of one to three picture stories. One group followed the 4/3/2 procedure (Nation, 1989), which involves three iterations with gradually increasing time pressure; for the other group the available time was constant. The extent of re-use of words and grammatical structures across task iterations was calculated using cosine similarity with tf-idf weighting (Manning, Raghavan, & Schütze, 2008), which adjusts for the frequency of words or trigrams, both within an iteration and across iterations and speakers. It was found that immediate task repetition had a strong effect on re-use at the level of individual words and trigrams, but increasing time pressure did not. The relationship between re-use and fluency was variable, but showed higher re-use for speakers struggling with fluency. We conclude that, if fluency development is to be stimulated by re-use of words and grammatical structures, it can be done with specific task repetition, whether under increasing time pressure or not.