2 of my kids had speech therapy for yrs. They are both PG but one scored -0- on articulation assessment at age 3.5. He scored very high on the tests requiring understanding. We tested hearing. There were lots of ear troubles. His fine tuned articulation didn't come till age 6, so I'd say 19 months--you're ok. We assessed another kid earlier and he's still in therapy (age 8) but he's also getting orthodontic assistance because of teeth/tongue issue.