My SEN resources are free to download at http://www.tes.co.uk/ as are hundreds of resources from other designers. You can search for what you think would be useful for the child you are working with.
If you are able to call on appropriate professional guidance, that would be the best thing to do. For example, can the child hear and see clearly? If the child does not seem to understand or speak as you expect, ask for a speech and language assessment. If there is family concern about delayed development in general, ask for a paediatrician’s opinion. And so on.
From a distance it is impossible for the writer to say which resources would be best in a particular situation. But they are offered in good faith and I hope they will be helpful.