I’m writing to you about my sister’s daughter. She just turned four, has been in speech therapy for a year both through school and with a private speech therapist that comes to the house, and I still cannot understand a word she says. She drops endings and her articulation is far from clear. My sister says that she is in a bad habit of talking too fast and when you make her slow down, you can understand what she is saying. But I think the root of the problem is the way she processes language. Something is definitely not right and I'm afraid she has severe speech problems.
If your niece is dropping (omitting) sounds at the ends of words, the speech-language clinician might want to try a minimal contrast word pair approach with her (e.g., show her two pictures where the only difference is the feature that she is omitting—one of a 'bee' and one that shows 'beat', 'beak', beep, 'beet') to help her understand what she is currently doing and how to change her production for different words. In other words, she needs to learn that she can still say “bee” when referring to the flying, stinging insect, BUT she needs to mark (say) the sounds at the ends of words for beat, beep, and beak because right now she says them all as 'bee-.' Initially, all we care is that the child MARKS the final sound—so if 'beak' is 'beat' that's okay. Ultimately, once she learns how to say 'k' then we'd want her to make that new sound correctly.
This is a good approach for other sound substitutions as well—e.g., if she is saying 't' for 's'—then pictures that depict such contrasts as ton/sun, top/sop, met/mess, hit/hiss, etc.
This approach works very well with children who have articulation problems but who are not apraxic. Children with apraxia can benefit from this approach, but they also need work with motor planning. The clinician will know if your niece is apraxic because that is one of the basic things we test for when a child has a sound production problem.
Relative to the language question, the clinician should be able to test for a language delay or deficit to rule that out.