This case study uses documentation as a tool for formative assessment to interpret the learning of twin boys with significantly delayed language skills. Reggio-inspired documentation (the act of collecting, interpreting, and reflecting on traces of learning from video, images, and observation notes) focused on the unfolding of the boys' nonverbal communication skills that helped inform planning and implementing instruction. Documentation is displayed, with an interpretation of the learning and a demonstration of the boys' strengths and competencies. The authors discuss how a public display of documentation sparked a collaborative inquiry among teachers, family, and the children themselves. Implications for practice outline guidelines in using documentation to assess learning. (Contains 7 figures.)