I havent been able to track down the disability requirements for NSW but
this should bring up some relevant pages - the first one which says cover A4 is a good synopsis of what is available plus a phone number to call for all the regions if you need them.
Usually the language disability requirements are an expressive or receptive language score greater than 2 Standard Deviations below the mean (standard scores <70) - your therapists will know what that means.
Looks like that link isnt working too well - if you press "go" it will bring up a list of documents (I hope!)