There may be a total lack of speech, with poor understanding of verbal and non-verbal communication. There is sometimes repetitive or echolalic speech (literally echoing what someone else says), or even well-developed speech,seemingly irrelevant to the given social context demonstrating a general lack of understanding of what others are talking about.Deficits in imaginative thought range from the inability to invent an imaginary world or to copy and use pretend play, through to the unimaginative use of toys or use of any objects inappropriately or for sensation only.