Yeah that’s super interesting. Ive never thought about the sighing before. I’ve started a newish job 9 months ago that I’m on the phone a lot for as well and I understand what you mean with the voice cracking after sighing. I feel like sighing is prompted by your body when it wants you to reset yourself (thoughts and muscles). So for me, I sigh during work if I’ve just got off the phone because my throat tightens more when I use my customer service voice. Sighing feels like it resets my brain to move to the next task and drop my muscle tightness. My voice is closer to my normal lower-register pitch after I sigh, but my normal voice can be really weak if I’ve been in customer service voice too long. Do you use different ‘voices’ to speak during the day? And are they different pitches?