Creating an oscillating circuit to sound an alarm using a speaker
First: Enable Alarm has to be connected to 5V to make the circuit work.

Second: Use a 32–50Ω speaker, as your current is limited to a few mA.

Note: when you use a CMOS chip as the 74HCT00, make sure the unused input pins are connected to GND or +5V, otherwise they will float and make the other gates oscillate, drawing lots of power and creating MHz noise.