Me neither (well, if I still stutter a little when I whisper), but I think it's right because we don't suffer from the stress and pressure that the idea of ​​communicating causes (because the stuttering remains a communication disorder). This may also be because singing/talking/whispering etc uses other neurological circuits, but I haven't found many sources for this hypothesis. Removing the neurological aspect of stuttering is just as wrong as removing the psychological aspect. The two are linked and influence each other.