Just keep working with it. Our son is 27 months old and still can't tolerate it for very long. He prefers to plug his trach with his finger and vocalize. It gives him more control. Our doctors said to keep trying the PMV, but said that some kids just never tolerate it at all.
Jakob, born Dec 02, Pfeiffer Syndrome, trached at 5 wks age due to mid-face hypoplasia, cranial vaultx2, monobloc, mid-face distraction, g-tube, pyloric stenosis, nissen, nasal stents, VP shunt, tonsils, adenoids, uvula all removed, tongue suspension, future pilot!!