The Words and Sentences Form, part of the third edition of the MacArthur-Bates Communicative Development Inventories (CDIs), is a comprehensive instrument designed for use with ages 16 to 30 months. To complete the inventory, parents document the child’s production of hundreds of words, record the child’s use of early forms of grammar, and provide written examples of the child’s three longest utterances. It is available in a pack of 25 paper forms.ABOUT THE CDIsThe MacArthur-Bates Communicative Development Inventories (CDIs) are one of the most widely used and recommended measures of language and communication for young children.Used in both research and clinical settings, these parent report instruments help SLPs and other professionals screen children, develop a prognosis for children with language delays, plan effective intervention, monitor progress, and meet mandates for including parent input in child evaluation.The third edition of the CDIs includes updated norms, additional tools, and more administration formats and helpful resources. Learn more about the MacArthur-Bates CDIs, Third Edition here.