Exactly. My fiancé stutters a lot more in her native Spanish (she's from Mexico) which she speaks to her family but she's comfortable around with her speech. But she speaks her secondary language, English (and some Polish (I'm from Poland)) she stutters less and it's because she's conscious and more alert of her speech. However, as you mentioned, she does stutter regardless if she's nervous or overwhelmed or tired - that's just something she can't control. Hope this helps :)