The revised version of the ABLLS  includes many new task items that were not included in the previous edition. There are numerous changes in the descriptions and criterion for individual task items, as well as in the sequencing of many task items.The Assessment of Basic Language and Learning Skills- Revised (The ABLLS -R) is an assessment, curriculum guide, and skills tracking system for children with language delays. It is based on the science of Applied Behavioral Analysis with Skinner's theory of Verbal Behavior along with research by Dr. Partington and includes 25 repertoire areas covering 544 skills.The ABLLS -R Protocol and The ABLLS -R Guide are two books in a series of publications from Behavior Analysts, Inc., that can help parents and educators with the process of identifying specific skills that should be the focus of intervention for a child with language delays.