Published online by Cambridge University Press: 15 June 2020
Narrow reading has the potential to reduce vocabulary load and to provide rich opportunities for developing collocation knowledge, but these benefits rely on narrow reading increasing lexical repetition within a text. Hence, interest in narrow reading has been limited by the relatively small lexical effect of narrowing reading by topic (Nation, 2013). Nevertheless, research in data-driven learning and teaching and language corpora has reported positively on learners using concordances in a manner comparable to narrow reading. However, the potential for concordances to provide an increased lexical-repetition effect has not been assessed. This study bridges this gap by exploring the degree of lexical repetition available in concordances and identifies corpus composition as a key predictor of lexical repetition. The study uses standardised type-token ratio (sTTR) to analyse concordances extracted from corpora at three different levels of homogeneity/heterogeneity. The results show large, reliable variations in lexical repetition resulting from variation in corpus homogeneity/heterogeneity, and so identifies concordance-based narrow reading as a possible means of overcoming the limitations of traditional narrow reading by topic. The results are discussed with reference to pedagogical implications for language learners, teachers, and researchers.