I am assuming that you reside in the United States or Canada. If this is the case- please contact your local school district and ask for a preschool readiness and developmental evaluation by the early intervention team. You will need to make this request in writing. Be sure to keep a copy for your records.
Together- you and the team should discover where to proceed. Good luck!
Also, you may wish to consider introducing sign language in conjunction with speech to bridge the communication gap for now.
Louise Sattler, Psychologist
Owner of SIGNING FAMILIES™