First off, the same answer applies. If the period of the wavelength is equal to the velocity, and the velocity is just under the speed of light, then the wavelength is as good as unusable in any practial sense.
Second, in both acoustics and EM, the term Hertz is used, which means "cycles per second". In both instances, to say that a wave length has "negative" cycles is retarded. Point two also stands.
Go back to your corner and shut up, kid.