Educational Impact and Implications StatementWords can consist of several meaningful parts, or morphemes, such as -ist in guitarist and re-in reuse. Understanding common morphemes helps children infer the meanings of new words. In this study, we tested the effects of working with an educational application (app) focusing on morphemes. Children completed app exercises such as sorting words or pictures according to their meaning, combining morphemes to build words, or identifying the correct word or morpheme to fit a sentence or picture context. We found that the app was effective in improving Norwegian second graders' ability to explain, understand, read, and spell words, including words which were not shown in the app, but which contained trained morphemes. The brief low-cost training produced long-term effects with a minimal burden on teachers.