Many Indigenous languages are critically endangered and faced with the urgent need to create parent-aged advanced speakers. This goal requires sequenced curriculum, effective teaching methods, students being supported to spend more than 2,000 hours on task, and regular assessments. In response to this urgent need the author followed a proven direct acquisition method and curricular design developed for Nsyilxcn and Interior Salish languages and wrote two beginner Tlingit textbooks and their accompanying teaching manuals. The author piloted the Tlingit textbooks with a cohort and developed a filmed assessment process. This article shares results of filmed assessments for Nsyilxcn and Tlingit, implemented by beginner and intermediate speakers. Recommendations are made for Indigenous language revitalization, including assessment methods appropriate to critically endangered Indigenous languages and strategies to create advanced speakers.