There were portable ones but I don’t think so

Oh yes, you are right about that one. I remember a princess or some person even fainting after listening to a speaking clock, though that happened even further back in time. Understanding how they recorded sound is actually fairly simple, once you have the whole thing set up in pictures in front of you. You just have to hold your hand to your throat when you make a loud sound and feel the vibrations making movements. The air between your mouth and a diaphragm is then basically compressed and relaxed in a fashion similar to waves on a pond when you throw a stone in it. That is one of the best visual representations I can think of. Now, when these air waves hit the diaphragm it also responds to the changes in the air density and vibrates in a similar fashion to your throat. Now, you just need to attach a needle (or stylus, as they prefer to call it) to the diaphragm and let it rest on the moving surface of a wax cylinder. The stylus will make a groove of varying depth as the cylinder turns and you will actually be able to "see" the sound that you made, or any other sound that was being recorded. It naturally follows that you can reverse the process and generate sound again when you run the stylus in the original groove on the cylinder. The groove will make the stylus and diaphragm vibrate and that in turn will make "air waves" that your ear can hear and interpret as sound.