My native language is Russian, the other one is Kazakh (not frequently spoken though), English is a first foreign language. Decent fluency is for all of these languages, but sometimes I can't say my name in all of them when meeting new people. Also if there is an unexpected question to me, I stumble for a while. In general stuttering occurs more in Russian. Good question, thank you! I'll track my speech to find out more, it is interesting.