It's largely disappeared. She still has the occasional word hang up, but nothing like before when it was every word. I wish that I could pinpoint something we did that helped, but it went away pretty much like it came. No explanation,  nothing causal. As a side bonus (according to her), she knows way more bad words than any other kid in her class because she was allowed to use potty words to break chains of stuttered words. We learned early on that bad words came out perfectly every single time.