I'm not a doctor and would like more information on this myself.
I'll try to explain what I feel happens.
Last year, I told myself that the reason why men and women sound so different is because they breathe differently using different muscles in their throat. Men tend to use more of the lower respiratory airway muscles while women use the upper airway muscles to breathe and speak.
Estrogen always plays a part in this because it somehow relaxes the upper airway muscles. Since women naturally have high estrogen, this is makes it easier for them to naturally breathe using the upper airway muscles.
Most children breath using their upper airway muscles and that is why children suffer from sleep apnea and upper airway obstructions a lot more than adult male and females.( male being the 2nd highest possibly because the lack of estrogen)
I believe its because their sleeping mind does not to tell them that they do not have the upper airway strength to breath this way..and it causes obstruction. Medically, there is still a lot unknown about this.
If you were to try and breath using your own upper airway muscles then your larynx would be pushed back into your throat. I'm guessing, because we're pushing the larynx inwards it tightens the vocals cords and causes them to become shortened( like females ). This is also why coffee makes it easier for people suffering from asthma attacks to breathe. It opens up the overall bronchial airways.
While I was training myself to naturally breath using the upper airway muscles, I noticed that the deeper my breaths were the higher my pitch got during the exhale release. So I started holding my inhale to produce a higher pitch sound and slowing talking it out, but still keeping my larynx pushed inwards to forever hold this position. I then started inhale and exhaling while using my neck muscles to hold the position of my larynx inwards. When I slept, ate, drank, laughed, talked, I would also keep breathing in this position.
I know it may sound confusing and its already lengthy but there is so much more that I did and believe helped me doing this.
tekla, mentioned something about the mind having control over the bodies ability as a joke, but I think its true. Even sneezing played a huge part in this because I used my mind to tell the muscles that cause sneezing to force out a sneeze using the upper airway muscles that were obstruction my airway; instead of just naturally sneezing using the lower muscles like my body normally did. It was like forcing the muscles to move and give airway access at a faster rate.
I'll stop now before this starts sounding even crazier. to you all. ol