One way to help young children develop their descriptive language capacities is to spend time discussing their experiences and memories. Most preschoolers won't remember detailed information after more than a few days, so start your conversation at an appropriate level. Asking leading questions can help cue children about what sorts of answers will make sense for a given question. Children may enjoy talking about toys they played with or places they visited recently. These can help you choose follow-up questions that will lead them to practice description.
Setting up activities that let children experience a range of sensations in a short time can provide a context for them to more clearly learn to distinguish sensory stimuli. It also provides an opportunity to teach and reinforce new descriptive words for sensory experiences that may be unusual for them. Use a texture book to teach kids about words like bumpy, scratchy, soft and smooth or provide a taste test of sweet, salty and sour fruits and vegetables.
In this activity, giving children a simple sorting task provides a context for discussion about the properties of different objects using descriptive terms. Bring a set of toys, colored blocks or other objects and ask the children to help you sort the objects into piles. You may give a rubric, such as color or size, or simply ask kids to pick out the objects that go together. The latter is more advanced, but offers a richer opportunity for children to think and reason independently. As you sort, discuss why each object goes in each pile to help children practice using descriptive terms accurately.
Similar to discussing experiences, this activity gives preschoolers a chance to think and talk about things they like in descriptive terms. Choose a few open questions and leading questions in advance, then use them to start a conversation with the children. For example, you might ask what foods a child enjoys, what his favorite part of the day is or what he likes about his mother. Suggest words and ideas if children have trouble expressing themselves, and follow up with questions about what the child likes about the things he names.