At the outset categorisation sounds easy and simple , given a set of flash cards and the child is asked to sort the pictures into categories , transport, fruits , vegetables, clothing.That would be the basic sorting. However Categorization is a difficult skill for children on the spectrum, and for children with speech disorders and cognitive abilities.Dwell a little deeper into categorisation, categorise transport into air, road and water, categorize household items. A little deeper , state the functions and ask the child to categorise given the functions of the object, categorise objects in a room, it gets a little trickier. Identify an object by the senses. For example it taste sweet/ sour. It grows on vines and is green or black in colour. It is a fruit. Name the fruit. Or try giving the objects in a category and ask them to name the category. Taking it a step ahead , discriminate among a given set of objects , pencil, pen,chalk ,door . What is not used for writing? Furthermore given a category , say body parts, ask the child to name 10 different body parts. Categorization is also very important not just as part of receptive language skills but enhancing expressive language skills. There are some good apps for iPad that help with categorization.
Tactus therapy has an app , category therapy. They have a lite version, which you can check out.
Smarty ears has an app by the name Describe it to me.
Pocket SLP app has also an app by the similar name Describe it.