First off you have to eradicate your fears of stutter, like this way: 'Just open your fking mouth and say whatever you want. If he or she can't tolerate your way of speaking, just leave him or her alone and that's just bc he or she is impatient and impolite, not your fault.' And if you still feel blocks, then you can instantly prolongate or split next words you wanna say apart from the blocked word in a seemingly natural time interval, and I think they will demand your insistent practices.