Have you been through any surgeries to help the speech. My son Caden is going in for a sphincter plasty later this month. He is 2 1/2, 100% tube fed, and has said almost nothing understandable other than Mama and even that is a little nasal sounding.
From what we are seeing, speech and swallowing seem to get overlooked in many 22q cases. Doctors get caught up in heart and immune issues and sort of disregard other things. Many kid’s bodies simply mature enough to get past the speech and swallowing. That is not the case with Caden and it sounds like it is not the case with you.
Make sure you engage your ENT and cranio facial team about possible corrective measures to advance speech. (z-plasty, sphincter plasty, etc.)