Then, please describe in more detail what you're interested in. If it's something theoretical, it's very simple: sometimes there's pain in the temporomandibular joint, which is why people with limited jaw movement begin to stutter. But most often, developmental stuttering occurs, which involves hidden sounds in the joint that negatively impact speech perception, leading to stuttering (as a reflex counteracting such jaw movements). Clicking or crunching sounds, for example, interfere with the perception of, for example, mainly consonants, when the jaw moves during conversation, so the body doesn't make any movements that would lead to sounds in the joint. Theoretically, this is how stuttering occurs.