We find it difficult to separate thought from language. Philosophers and linguists have given much attention to the question of whether we can think thoughts that we cannot vocalise; whether naming things differently means we actually perceive them differently. It can be hard for some of us to realise that people who have learnt English as a second language can be eloquent and fluent in their first language, or that limited English can express complex thoughts. A friend who teaches in high school was telling me today how he likes to use philosophy class to demonstrate to his colleagues that their ESL students are in fact subtle and creative thinkers, though they sometimes struggle to find the right words or correct grammar to convey their ideas.
Young children are learning thought and learning the world as they learn language. We usually measure their growing understand through language. But we would do well to remember that they may be thinking deeper thoughts than they yet have the power to say.
Especially when we work with children whose language development is not their greatest strength, we should not assume they only understand as well as their grasp of language suggests. We should seek out activities that allow them to exercise their minds even if they are not ready to exercise their words.