Three points.
One, paradoxes like "Everything I say is a lie," are entertaining, but flawed. The clear resolution is, as has been said, to conclude that they are lying. It would not follow that everything they say is a truth, however. Better, would be "This statement is a lie."
Two, quantum mechanics are incomplete in this time. This does make them harder to interpret: however, the direct observations cannot be questioned. Further, they are always going to be incredibly complex to explain. They are hard to imagine, and very little behaves similarly on the scales we're used to. The fact that your time has not yet reconciled them with macro knowledge makes it all the harder. However, as with all science, it is impossible to explain to someone who does not want to learn, as it sounds like this Papa Legbe is.
Third, on light and sound, they are quite intimately related. Waves are not composed of a substance, so the only way to tell the difference between two kinds of waves is to examine wavelength, freqency, and medium. The former two could be made equivalent between a sound and a light, so we are left with medium, and this is important.
Two waves may be identical, but what carries them? Sound is transmitted by physical matter: it manifests as vibrations in solids, liquids, gases, and other such states. Light does not require a material medium, however. This is the crucial difference, and for that reason its properties are very different. The waves of light are carried by the field of dimensions that everything exists in. They move through space, because of space. (This is why the speed of light is such a limit: light itself is defined by the spacetime dimensions it exists and moves in).
It's a few years before technology advances to the point that this can be proven (it's possible to change the medium of a wave from matter to space, and vice versa, turning light to and from sound) so it's fine if you don't accept my word, I just thought you'd find it interesting.
The speed of sound varies with medium. The speed of light is simply what that speed is, when the medium is space. As, on a quantum level, we are made up of similar wavelengths, if any matter tries to reach the speed of light, we would observe some very odd behavior indeed because part of what defines light is that it has quantum mass. For a non-quantum mass to move at those speeds through the mediums of space and time, spacetime would bend and stretch as a result.
This is very hard to explain, and harder still to visualize. I am sorry.