Categorizing is one of the building blocks in the Language Processing Hierarchy. This hierarchy found to be extremely helpful in determining starting points for interventions and therapy.  The ability to categorize items is a precursory skill needed for children to continue to understand and develop their language. At a young age, our brains begin to sort, organize and connect new information to previous experiences. So before children can tell their teacher which characters are in the story would most likely be classified as protagonists ( requiring the student to identify possible positive character traits for each character and then group all the characters with had similar traits ) they need to be able to understand the different, concrete ways students can group items. This process takes seconds for a person without a language disorder since their brain is already set up to execute this task in the proper way.  Our students need help to make this process become fluid. A study by LaTourette and Waxman 2018 showed that providing toddlers with just two labelled examples from a category was sufficient in initiating the process of object categorization and allowed them to add unlabelled items to their categories. When teaching categories start with ones of relevance.  If they are in a home setting maybe start with categorizing familiar foods, toys, clothing, cleaning supplies ( so they know what not touch ) etc.  If they are in an academic setting I suggest things they are will be seeing in school.  Groups like school supplies, food (maybe focusing on what is served in their cafeteria), and types of games they will play in gym or at recess, etc.  Then, expand from there.