Not at all - a speaker and a microphone are essentially the same device, though optimised in two different directions - making a standard speaker vibrate will cause the driver coil to excite, and exciting a mic will make it vibrate.
Try explaining how that works with a CONDENSER mike.
Yes, a moving coil speaker and a DYNAMIC microphone as theoretically interchangable, but there are practical limits. Using a mike as an earpiece can be practical in a pinch (if generally very tinny) but a speaker as a mike is generally a non-starter. Optimised mics generate signals in the 100mV or less region. A speaker in the same role may be lucky to generate 1µV - that's well into the realm of ultra sensitve amplifiers, yes, it can be done, but even then the audio is generally swamped by the effects of imperceptible air currents and temperature changes. In circuit it isn't connected to such a sensitive pre-amp: it goes to a power amp OUTPUT instead
It's one of those things that asserting blindly is nothing more than intellectual knob waving. In practice it will not work just as the refined chap stated. Claiming otherwise simply shows ignorance.