Investigating the Effects of Adding Explicit Teaching and/or Signing to Story-Based Vocabulary Intervention for School-Aged Children With (Developmental) Language Disorder.

Eighteen school-aged children with DLD or language disorder associated with a biomedical condition (14 DLD, 3 autism, 1 genetic disorder) at a specialist school in the UK each received 8 weeks of one-to-one vocabulary intervention, twice a week for 30 minutes (16 sessions total). Every child worked on all four conditions: story-only (reference), story plus explicit teaching, story plus signing, and story plus both. Forty-eight target words (24 verbs, 24 adjectives) were randomly allocated, 12 per condition, with two counter-balanced word lists so that words signed for half the group were not signed for the other half. The order of conditions was randomised per child. Outcome assessors were blind to which condition a word had been taught in. Intervention was delivered by six SLTs (including the first author, who designed the intervention) as part of the school's usual therapy provision. Children progressed through story sets at their own pace based on session probes, so the number of words taught varied (mean 42.22 out of 48; range 32 to 48). Analysis used Bayesian multilevel ordinal models.

Primary outcome (word definitions, scored 0–3): All four conditions produced improvement from pre- to post-intervention. The reference (story-only) condition itself led to gains with 99% probability. The three experimental conditions (adding explicit teaching, signing, or both) produced greater progress than the reference condition with 100% probability. On average, participants went from scoring full marks on about 9 words pre-intervention to about 21 words post-intervention across all conditions. Secondary outcome (sentence generation, scored 0–2): All conditions improved; the three experimental conditions showed greater progress than reference with probabilities of 90% to 94%. Research Question 2 (does combining explicit teaching and signing add benefit over either alone?): No. Neither the + explicit nor the + sign condition was worse than the combined condition, and the bulk of the posterior distributions actually suggested the single-component conditions may have produced slightly more progress than the combined condition, though the evidence was not strong enough to conclude the combination was definitively inferior. Exploratory analysis found no significant correlations between age, standardised language scores, and progress in any condition (lowest p = 0.13).

If you are teaching vocabulary to a school-aged child with DLD using stories, adding one extra layer — either explicit teaching (definitions, example sentences, retrieval practice) or augmentative signing alongside the spoken story — will likely produce more word learning than the story alone. You do not need to do both at the same time; the combination did not outperform either single addition and may have slightly reduced progress, possibly because asking the child to track and produce signs while also processing explicit verbal explanations increased cognitive load. Signing is the more time-efficient option: it can be layered onto the story in real time (about 3 minutes per story set) versus about 7 minutes when explicit teaching is added. If you are not confident in signing, explicit teaching is a valid alternative. Choose based on the child's preference and your own skill.

Only 18 participants at a single specialist school, so the findings may not generalise to community settings or to children with different language profiles. No follow-up testing: it is unknown whether the vocabulary gains were retained after the 8-week intervention ended, and whether different components (signing vs. explicit teaching) affect long-term retention differently. Pre-post design without a separate control group; the within-subjects comparison is informative but does not rule out practice effects or maturation over 8 weeks. Age and standardised language scores were strongly negatively correlated (r = −0.73), meaning older children in the sample had lower language scores, which limits the ability to interpret age or language-level effects. The first author designed the intervention and was one of the six SLTs delivering it, which introduces a potential bias in how the protocol was implemented. The study targeted verbs and adjectives specifically; findings may not extend to nouns or other word classes. Children progressed through material at different paces, so the number of exposures per word varied (mean 17.6 across conditions), making it hard to isolate the effect of dosage from the effect of the added component.

The study was funded by Moor House School & College, the same institution where it was conducted. All authors are employed by Moor House School & College. The first author designed the intervention and was one of the six SLTs who delivered it to the participants.

Do not read this as evidence that stacking explicit teaching and signing on top of a story is the best approach. The combined condition did not outperform either single addition, and the data hinted it may have been slightly less effective, possibly because asking a child to produce signs while also processing verbal explanations overloads working memory. If you are already using one of these strategies well, adding the other is unlikely to help and may do more harm than good.