To preface, My career fields are early childhood education and childrens mental health, so I may be biased, but I also have years of experience and knowledge. All young children have occasional dysfluency. Children are also very in tune w the non-verbal communication and feelings of their adults. If sn adult is uncomfortable w a child’s dysfluency, it will show in their face, at the very least. A sensitive, intuitive or aware child will pick up on this discomfort, and will try to “speak better”. If this combines with certain temperaments, and whatever biological stuff predisposes you bumpy speech, impactful dusfluency (blocks, avoidance behaviors etc) can begin as early as 3. It then snowballs as they grow. This theory is also backed up by SLP s who specialize in dysfluency -to differentiate from SLP with minimal or no training in our issue. (Most SLP training programs require/offer minimal, outdated, or” non-proven” training. )