VietTESOL International Convention 2026

Long-turn second-language (L2) speaking requires learners to sustain real-time conceptualisation, formulation, articulation, and monitoring, with lexical retrieval playing a central role in maintaining fluency (Kormos, 2006; Levelt, 1989; Segalowitz, 2010). This repeated-measures correlational study examined whether breakdown fluency in time-pressured monologic speaking was better explained by topic familiarity, perceived lexical retrieval difficulty, or their relationship. Thirty-nine low-intermediate Vietnamese EFL learners completed five IELTS Speaking Part 2-style tasks. After each task, learners rated topic familiarity and lexical retrieval difficulty; their speech was analysed for silent pause frequency, mean pause duration, mean length of run, repair rate, speech rate, and a composite breakdown index. Mixed-effects models controlled for vocabulary size, task order, participant variation, and task variation. Results showed that greater topic familiarity was associated with fewer silent pauses, shorter pauses, longer runs, faster speech, and lower overall breakdown. Perceived lexical retrieval difficulty predicted additional variance across primary breakdown measures and was the stronger predictor of pause duration, repair rate, and the composite index. Mediation analyses indicated that lexical retrieval difficulty partially accounted for the relationship between topic familiarity and breakdown fluency. The findings suggest that familiar topics support L2 long-turn fluency partly by reducing lexical retrieval pressure.
Keywords: Topic familiarity, lexical retrieval, breakdown fluency, L2 speaking, monologic speaking, IELTS Speaking Part 2, Vietnamese EFL learners, mixed-effects modeling