this has happened to me many times,i was severely classic autistic up to around 29 when my challenging behaviors stabilised and my verbal capacity suddenly developed due to the intensive daily therapies i was having,i am now moderate classic autistic with mild intellectual disability.
i have been spoken for many a time,whether its on the street or in a professional sense, people see me as useless.
i cant fault the social services learning disability [meaning intellectual disability in the US] team though whove supported me since a late teen because all but one of them uses person centred aproach/planning [look it up,im not that good at explaining],the pyschiatrist speaks for me all the time and makes massive assumptions about my mood and sleep and opinions, i hate her,i made a big complaint about her last week,i cant write so i had to get my staff to write it which was bad as i didnt want anyone else here to see it.