Vocal onset energy

The first vocal sound created by our bodies happened before our ever having taken the first breath.  What was this impulse met by physics that created our first shaky vocal tantrum before the first lung filling plop of air into our body; dropping like a stone into the recesses of our half-pint sized lungs that had quite recently been filled with fluid, before this fluid was squeezed out of us as we invaded this plain of existence, time, and experience?

This sound creaking from our acorn sized (if) larynx was our first attempt to resist gravity; pushing against this new weighted blanket that is the earth's atmosphere (remarkably new digs compared to our previous address).  A spasm-ed, sphinctering gesture of protest that eeked out a dribble of a vowel sound, then, and inward gale of God given breath, filling us to draw back and do it again, but stronger than the first; trumpeting our arrival, like the first swimming strokes of a newborn sea creature, but internally driven and externally experienced as sound, while we pulse and lunge with our newly experienced pure waves of tone rather than the newly experience body moving strokes that thrust a newborn dolphin's body through a resisting watery atmosphere. These waves of tone, what principals these?  What is vibrating?  What is its fuel source?  Why is it so loud?