Yeah, I have similar experiences. When fatigued, my English speech stops being as fluid and my stuttering intensifies (akin to higher stress levels). I've also

Yeah, I have similar experiences. When fatigued, my English speech stops being as fluid and my stuttering intensifies (akin to higher stress levels). I've also observed that in those cases, mixing language becomes much more common, incorporating words from my native language in English, and vice-versa too.