Sure i was thinking to write everything in detail but as my english is not that great so i decided just to give you reference... According to book stuttering is a anxiety panic cycle , when ever we are in anxiety, depressed or something like that you must have also felt that we feel it in our chest and stomach... so what happens is that as we sturrers have picture in our mind that we are surely going to stutter and that creates anxiety in our head .... now to speak correctly we need a proper function of diagrphram muscle that contracts and relax which results in air being released and vaccum being created and then air again taken into lungs and pusehd again ... so when we get panic/anxiety our diaghram functions also get effected resulting in a diaphhragm stucked in a place and not able to contract/relax results in blocking (think it like a Kangaroo in a middle of a road when it sees a car headlight it cannot decide wether to go back or keep moving so as a result it just freezes/blocks right in the middle of road and get hit by a car) ... same thing happens to our diaghram muscle during panic it just get stuck , which results in a block (80%) of stutter is because of this rest 10-20% is because of articulators like mouth, tongue for that we can speak from our chest and that can fix this issue but anyways and the thing is that that diaghram is not in our control thats why we are able to breath when we sleep because its involuntary muscle... but the thing that we can do is that use coastal diaghram which is another muscle and totaly in our control for breathing so that when we get panic/anxiety during speech we can control our coastal diaghram and not let it hang resulting in blocking...there is a breathing technique called diaghram breathing , which we have to practice and master it so that we start to breath with costal dighram instead of other diaghram i forgot its name... according to me when we walk , we also use coastal dighram for breathing because we need more oxygen and thats why we are able to breath correctly results in much much less or almost no stutter... + when we walk we also speak with our chest you can read this book called (Beyong stammering by Mcguire Program). sorry for bad english/grammer