I would hope that there is a team around the child including a Speech-language therapist and Occupational therapist - if not then prople like those at TalkLink (http://www.talklink.org.nz/ ) can be invaluable at providing information, assessments and a 'fresh pair of eyes'. How does the child communicate at home / with peers?
I follow a blog written by a Dad about the challenges of having an (almost) non-verbal child http://www.schuylersmonsterblog.com/ and although they are in the States, the insights he provides are fantastic. The Dad's honestly can be quite confronting!
Jane