Mama, at this point, you probably know more about raising a child with autism than most of us amateur astrologers.
Your little girl's chart has Saturn in the 3rd house of communication. Saturn is related to disappointments and delays in the house where it is located. But Saturn does respond to patience, hard work and perseverence. You are probably working with your daughter now on various interventions.
Years ago I had a good friend whose little son was diagnosed with autism, and who wasn't speaking. Interestingly, she was a graduate student at the time he was diagnosed -- in speech therapy. She began working with her son in sign language. I just looked it up. Apparently teaching sign language went out of favour for a while, but now seems to be approved in some situations.
https://autismcanada.org/living-with-autism/treatments/non-medical/communication/sign-language/
Mercury is the planet that rules communication. With her Mercury in Aquarius sextile its modern ruler Uranus, you little one may respond well to electronic means of communication. She also has a nice sextile between Mercury and Venus. Venus is the generic ruler of the arts, so she may enjoy finger painting, making music, or dancing.
Usually trines are the easier aspects for people. Uranus will make a trine with your daughter's moon next year and in 2021, so you will hopefully see some improvement then. Uranus rules the unconventional as well as electronics, so this may not be what I would think of as everyday speech so much as a novel form of communication.