Semantic Pragmatic Disorder is language/communication disorder, commonly found in children on the Autistic Spectrum. The disorder's validity as a sub type of developmental language disorder, which is where it was originally defined by Rapin and Allen back in 1983, has been questioned on and off since it's introduction because of the autistic features the children often show. The professional community is slowly extending the boundaries of the spectrum to acknowledge disorders such as SPD and high functioning autism that can blend into the realms of "normality".

Children affected by this disorder have difficulties in the area of the "triad of impairments", typically associated with Autistic Disorders, ie. social interaction, communication and imagination. Their autistic features, however, are mild, but it is important to recognise these when supporting the child.

Children are usually first identified as having this disorder by the noticeable delayed language development. Parents begin to feel that there is something not quite right, but just cannot put their finger on the problem. Language starts to appear eventually, but there is often a severe impairment in understanding and using language and applying linguistic rules in conversation. Typically the child will sound odd and stilted in conversation, using memorized phrases inappropriately, out of context, echoing language like a parrot, not sticking to the topic of conversation, not knowing what is being talked about, and not knowing what to say in return to a question asked. He/she will take language quite literally, and will struggle to understand the many idioms in use in the English language today, i.e." raining cats and dogs" will mean just that to a child with SPD!

source: hi2u.org