Abstract
Vocabulary is one of the five core pillars of reading development (National Reading Panel, 2000), and substantial evidence links vocabulary knowledge to reading comprehension (e.g., Elleman et al., 2009) and word learning (e.g., Storch & Whitehurst, 2002). The Institute of Education Sciences’ (IES) What Works Clearinghouse (WWC) Practice Guide on foundational reading skills identified teaching academic language, including inferential and narrative language, as a key instructional recommendation. At the time of publication, this recommendation was supported by minimal evidence (Foorman et al., 2016). To build upon this work, this review examined studies published between 2014 and 2025 that included at least one vocabulary outcome for students in kindergarten through Grade 3. The systematic search yielded 23 studies comprising 6,030 participants. Of these, 30 significant findings were identified (i.e., effects), including 27 significant positive effects on proximal measures. Three studies found significant effects on a distal standardized measure of vocabulary knowledge (August et al., 2021; Hassinger-Das et al., 2015; Lovett et al., 2017). Thirteen of these 23 studies were rated as high quality according to WWC standards. Effective practices across studies included: (1) identifying high utility target words to explicitly teach; (2) explicit teaching of target words using child-friendly definitions and visuals, repeated exposure, and discussion with target words; and (3) integration of vocabulary instruction within academic content (e.g., science or mathematics) and with connected text. These findings support and expand the evidence base for the academic language recommendation in early reading instruction.
