Can somebody help me understand how this circuit works, why it oscillates and what the conditions for the oscillations mean?

I'm fairly new to electronics, accidentally made an oscillator with this circuit. As showed in the pic, R5 would be an 8 Ohm speaker, or otherwise there could be an LED to show the oscillation. The transistors I used are basic NPNs (S8050).

As far as I understand, the reason why it oscillates should be that it's quite an unstable circuit, C2 charges rapidly but when it reaches a certain voltage, it shuts off Q2. Then it discharges on R6, with a time costant R6*C2 (which is partly responsible for the oscillation frequency), and when the voltage drops below a certain level, Q2 opens and the process repeats. However, I have no idea what the role of C1 is.