Poor language skills undermine academic success which eventually impacts socio-economic outcomes andquality of life. When deficient language skills are first noticed in young children there is relatively little timeavailable to close the gap before they are faced with the increased language demands of formal education aswell as the potential for academic failure. For the 8-13% of preschool children with impaired language skillslanguage treatments that are faster and more effective are urgently needed. Yet current treatments arenotoriously protracted and expensive and the effects of treatment can be weak. There is a growing call amongscholars to step back from the business-as-usual approach to treatment research in favor of a systematicapproach that integrates promising theoretical frameworks with experimental manipulations designed to isolateand enhance the effective components of treatment approaches. This grant proposes to leverage insights fromthe statistical learning perspective on language acquisition which explains rapid unguided learning sometimeseven in the presence of impaired language. The grant proposes six treatment studies that target two groups ofchildren with poor language skills. Late Talkers are children (ages 2-3 years) who are identified by theirlimited lexicons. Preschool children with specific language impairment (ages 4-5 years) show marked deficits inthe use of grammatical morphemes. Parallel sets of studies with these two populations will determine theextent to which treatment variables enhance or detract from treatment efficacy across language domains. Thegoal of this work will be to identify specific treatment methods derived from general learning principles thatclinicians can employ to enhance learning outcomes for children with impaired language skills.