I wish I would understand even a fraction of the stuff that's going on with software synths. Every couple of years I get this fancy idea of "I'd really like to create some sounds/music", which usually ends up with me aimlessly manipulating digital knobs and switches on some massive UI, creating weird sounds with no real structure and changing all the default settings. The other option being something like FruityLoops…
Open your mouth in a 'neutral' position and make a sound. That's an oscillator. Tensing your throat will change the waveform (on a synth that would be square, pulse, sawtooth).
Purse and widen your lips, make a 'wow' sound: that's a low-pass filter (which cuts off higher sound frequencies).
Make a 'shhh' sound: white noise. Purse your lips, make it sound like wind blowing: band-pass filter (which only lets certain frequencies through).
Turn that wind noise into a whistle: now you're adding filter resonance. As that noise becomes a pure tone, the filter becomes self-oscillating.
Add some vibrato to your sound (like an opera singer), or change the pitch (like a siren), and you're adding modulation.
Doing this in a room, or large hall: now you're changing the reverb (reverberation). In a canyon with echoes: delay.
Often, this is also a useful method to work out how to program a subtle or complicated patch (a sound preset on a synth, so named because early modular synths used telephone patch cables to make the necessary connections).
Aside: I've often wondered what a human choir, making 'synthy' sounds, would be able to do with something like Jarre's classic Oxygène IV...