Thx my friends for your replies :) I heard about MacGuire program but maybe one day, i will pariticpate to one of their stage. 2 years ago, i participated to a french speech therapy, Impoco programif you've heard about it. It consist about doing muscle contraction for each syllable. It worked for me but just during the stage but i guess i have to struggle and to find the lost ingredient to make it work in real life. Its really hard to speak about program like that when you are living in Africa, for exemple, the stage i passed cost me 850€ which is 2-3 time the salary of an engineer in tunisia !!!!!! The smic here is about 150€ so imagine what 850€ means.