Can you read me? Investigating textbook reading materials and the coverage–comprehension relationship in the English and French foreign language classroom

Reading development in the foreign language (L2) classroom presents an important pedagogical challenge. A ubiquitous source of classroom input is the L2 textbook, in which a variety of reading materials are often featured. Various theoretical considerations for the design of didactic materials may be distilled from Second Language Acquisition (SLA) research, but it remains unclear to what extent L2 textbooks align with these principles. A directly related question concerns the relationship between linguistic characteristics of texts and L2 readers’ comprehension. One crucial dimension in this relationship is lexical coverage, that is, the proportion of words in the text which are known to the reader. An important shortcoming in prior research into lexical coverage is the near exclusive focus on intermediate–advanced L2 learners of English. This doctoral dissertation set out to address three objectives: (1) investigate lexical characteristics in a self-compiled corpus of reading materials retrieved from L2 textbooks used in Flanders, (2) investigate the development of lexical and grammatical complexity in this same corpus, and (3) conduct a study into the relationship between lexical coverage and reading comprehension in adolescent, secondary-school L2 learners from Flanders. The focus in each of these three objectives is consistently on two L2s: English and French (i.e., the two main L2s in Flemish secondary education). This cross-lingual focus is both theoretically and pedagogically valuable in that English and French tend to be learned under vastly different input conditions in the Flemish context, mainly as a consequence of out-of-school exposure (which is high for English but low for French; Peters, Noreillie, et al., 2019). The lexical corpus analysis indicates that vocabulary loads (that is, estimates of vocabulary knowledge required for text comprehension) increase relatively systematically in the English but not the French materials, which may hamper vocabulary and reading development. In both the English and French materials, a vast number of high-frequency words are never represented (20–30% of the 5,000 most frequent flemmas) and many words are exclusively used in one text (ca. 50% of all introduced words). In the complexity analysis of the textbook corpus, several complexity features demonstrate considerable increases across grade levels. In a regression model where complexity features serve as predictors and the texts’ intended grade level as the outcome, considerably more variance is explained in the French corpus (43%) compared to the English corpus (23%). Thus, a greater evolution in linguistic complexity (particularly grammar) is present in the French materials. The coverage–comprehension study reveals that lexical coverage significantly predicts reading comprehension in French, but not in English. A coverage threshold at which comprehension accelerates cannot be observed in either language. A possible reason for these results is that the effect of lexical coverage might depend on a complex interplay with numerous other factors (e.g., grammar knowledge). Overall, this dissertation contributes to current understandings of L2 reading materials and the coverage–comprehension relationship, particularly by focusing on French in addition to English. It also carries methodological implications for cross-lingual corpus and behavioural research.