Parents of children enrolled in Grade 1 at partnering schools will receive consent materials and those who provide consent will complete a brief background/demographic survey about their child. For children whose parents provide informed consent, research staff will (a) ask their educator to confirm basic English proficiency and lack of profound disabilities or behavior issues that severely impair classroom functioning, (b) seek the child's assent to project activities, and (c) administer a language screener in a quiet location at their respective school, either in a small group of other consented children or one-on-one. In order to qualify as eligible for the intervention phase of the study, consented children must: (1) be enrolled in Grade 1 (per educator or parent report) (2) score at or below the empirically derived cut-score on the OWL screener (obtained via direct testing), (3) exhibit at least basic skills in speaking and understanding English (per educator report), (4) not exhibit behavioral difficulties sufficiently severe to prevent participation in the intervention (per educator report), (5) not have a severe disability that would prevent participation in the intervention (per educator report), (6) assent to study activities. Children who meet all eligibility criteria, including scoring below our cutoff on the language screener, will be categorized as potentially eligible for enrollment in the intervention phase of the study. In order to enroll children within a particular school, the investigators must identify a minimum of 6 eligible participants in that school. The investigators will cap the child participants per school at a maximum of 20 in cohort 1 and 10 in cohorts 2 \& 3 to allow for later analysis of nested data (children nested within schools; the investigators need 40 schools for appropriate statistical power). Children who are identified as potentially eligible but who attend schools with fewer than 6 total eligible participants, or who consent to the study but have not yet been screened by the time the investigators identify 20 eligible participants in cohort 1 and 10 in cohorts 2 \& 3 will be excluded from further participation. In schools in which the investigators have more than the allotted potentially eligible children, the investigators will randomly select the cohort-specific number to enroll in the intervention phase of the study. Children enrolled in the intervention phase of the study will be randomly assigned to receive the Let's Know! intervention or to a business-as-usual control condition. Random assignment will be conducted by Dr. Flemming at KUMC, who will be uninvolved in recruitment, screening, and pretest activities. Prior to intervention start, all enrolled children will complete pretest assessments to measure the lower-level and higher-level language skills targeted by the Let's Know! intervention, comprehension skills, and other abilities (i.e., covariates and moderators for addressing Aim 3). All direct child assessments are listed in Table 1 above. All child direct assessments (screening, pretest, curriculum-aligned measures, posttest, follow-up) will be administered by trained research staff in quiet locations at children's respective schools; alternative arrangements to conduct assessments in the PIs' research laboratories or community locations (e.g., public library) will be made as necessary (e.g., if a child moves into a new, non-partnering school). All but the language screener and Gates-MacGinitie Tests of Reading will be administered individually, with the two exceptions administered to small groups or 1:1, dependent on scheduling. Screening and assessment sessions may be audio or video recorded to allow for accurate scoring and analysis. Following pretest assessments and assignment to conditions, research staff will provide the Let's Know! intervention to small groups of 3 to 5 children allocated to the intervention condition at their respective schools. The Let's Know! intervention provides instruction in the domains of text structure, integration, word knowledge, and grammar; as such, it targets key lower-level (vocabulary) and higher-level (e.g., story grammar, comprehension monitoring, inferencing) language skills to support listening and reading comprehension. The intervention features manualized, soft-scripted lessons that will be provided in small groups of 3-5 children 4 times a week for 25-30 minutes. The lessons are organized into four instructional units that are delivered over 22 weeks. All four instructional units emphasize repeated readings and explorations of commercial texts, with two units comprising narrative books and two comprising expository books. All intervention lessons will be videotaped for purposes of monitoring implementation and coding fidelity. If an individual child misses a session, this will be documented and the session will not be made up. If an entire group misses a session (e.g., due to a field trip/school assembly), the interventionist will wait and deliver that lesson during the next scheduled session (e.g., one group may miss Animals 12 due to a Tuesday assembly; the interventionist teaches Animals 12 at the regularly scheduled Wednesday session and proceeds from there). Children in the control condition will participate in study assessments as noted above but will not experience the Let's Know! intervention. They will receive business-as-usual classroom instruction and supports within their schools. That is, the child's family and school will provide instruction and support for children in the control condition as they typically would for any child not enrolled in the study. The investigators will document the interventions received by children in both the intervention and control conditions.
