I speak 6 languages fluently. I stutter if I can only think of one way to say something. I normally only speak 3 languages daily, (English, Spanish & Polish.) If I have to speak Polish it's generally harder since I don't have as wide of a vocabulary as I do in English or Spanish. (Although it's mitigated slightly by the fact that Polish has very flexible word order.) However, it's easier for me to tell a story in Polish if it's about something simple and I can switch around words, than it is if it's about history in English and I can't switch words. You'll stutter less and less if you get better at English. Trust me. Unfortunately you might need something like C1 level English before you can speak comfortably. Good luck! \[Edit\] It will also have to do with getting comfortable in a language. I hadn't spoken French in about 3 years, (conversations with taxi drivers from the Congo 2x a year don't count,) before I went to France last month. The first 3 days were rough. I just acted like my French had gotten rusty. In reality, my French was totally fine, I was just not used to speaking French.