English language learners are increasingly entering classrooms using student-centered instruction that places a greater emphasis on spoken language. While active learning is beneficial for a range of student outcomes, these practices force language learners to carry a heavy cognitive load in a complex and challenging environment. This experiment varied the complexity of the learning experience across a large, multi-section active classroom by presenting different versions of an in-class worksheet to each section. This experiment was controlled for instructor, topic, content, and environment, and treatment groups varied only in lexical density and amount of the language used on a worksheet. This modest variation in instruction corresponded to significantly improved learning as demonstrated on a pre- and post test for international students who represent a conservative proxy group for language learners. These data imply that the effectiveness of active learning strategies can be enriched for English language learners by designing learning materials that are simplified in language.