Purpose: The aim of this study was to examine the effects of a rich vocabulary intervention on the vocabulary learning and comprehension of third-grade students with language learning disorders (LLDs), including speech and language impairment and specific learning disability in reading. Method: The study used a repeated acquisition design, a single-case design involving the repeated delivery of a vocabulary intervention on different sets of five vocabulary words and repeated pre–post measurement of students' vocabulary acquisition and comprehension of the different stimuli targeted each week. Students in the treatment group ( n = 3) had 3 weeks of a baseline comparison phase, where they were taught sets of five untested vocabulary words ( n = 15 words), and 5 weeks of a treatment phase, where they learned sets of five tested vocabulary words ( n = 25 words). Vocabulary was measured using a 9-point Total Semantic Knowledge measure that included an oral definitions component and a receptive vocabulary assessment called Context Test Questions. Comprehension was assessed using a passage-level sentence verification technique. Results: There was a statistically significant, moderate effect on vocabulary learning. No treatment effect was found on students' comprehension. Following the maintenance phase, students scored lower on the vocabulary maintenance assessment than at posttest, but about 1 point higher than their pretest scores. Testing effects were evident on the comprehension measure following the maintenance phase only. Conclusion: These results suggest that explicit vocabulary instruction led to immediate improvements in taught vocabulary but not comprehension skills for the third-grade students with LLDs in this study. Supplemental Material: https://doi.org/10.23641/asha.31930236
Harker et al. (Wed,) studied this question.