My son has apraxia and he started at PTC - Pediatric Therapy Center off 59 (around Gessner) we recommend Sandra if she is there and also Amy Greebon. Call them they will check your insurance and evaluate etc. Early intervention is key. Also check with your elementary public school. They should be able to eval and he may qualify to be seen once or twice a week.
When my son was 4 he went to PTC once a week and to the school once a week. He was also going to a private school so even though yours is at montessori, he can still be evaluated and possibly seen at your zoned elementary school.
Hope this helps
C.