This text adaptation task poses a difficult challenge for us in efficiently producing accessible content for learners from many levels—not only for our Stories, but also for Podcasts and other features across Duolingo products. So, we’ve built semi-automated machine learning systems to aid in our content creation process targeting various language proficiencies, as measured by the CEFR standard. In particular, we’ve built the CEFR Checker to help transform and check that content across languages appropriately targets beginner, intermediate, and advanced learners. Today, we’re making this tool available to language educators and the general public as well! Its use and methodology are described in some detail below.