I have been doing a course with NAS and the suggestion of using PECS has come up. But am I right in thinking they are more for people with quite limited speech as in single or maybe 2 word sentences? DS (4) is speech delayed for his age but he can easily string a sentence of 8 or 9 words together. It's not proper unstilted conversation yet but he's a lot more advanced than other children in his SS reception class.