I'm somehow on the other side of your situation OP, I'm a foreigner living in Turkey and want to train in Turkey as well for a while (I study architecture). It doesn't bother me because for me architecture doesn't require us to speak a lot but still it worries me a bit because Turkish is still a different language for me. I think you need to figure out what are you going to do exactly, like what kind of job are you going to do when you go to Japan within the range of your profession, and work on your skills accordingly. I think you have to put extra time and effort to be on the same level as non-stutterers. But that shouldn't discourage you at all. Tbf I admire your enthusiasm, I love Japan and Japanese culture and architecture and I tried to study Japanese for a while, it was fun but had to drop it for while to work on my Turkisg, so I understand your struggle. God bless and good luck Kardeşim 👍