They're also going to be unable to see, since their eyes are sized and designed for more wave input. There's a reason insects have compound eyes. I could look up the math / physics... but the gist is, that the pupil needs to be a certain size to let thru wavelengths (iirc).
Edit:
Squeaky voice, at very low volume: Their speaking pitch will be 3,400 cycles a second (vs. 200 cycles a second) - (300x reduction in size roughly - square root == 17). And they'll only able to generate 1/17th (or less, not sure of the math - diaphragm is basically flat) of the volume of compressed air from smaller lungs.
Hearing reduction: eardrum reduction, means the lowest frequency they can hear is 340 cycles a second (vs 20 cycles a second). The eardrum is unable to respond linearly to density variations near the source of sound, and the ability to distinguish differing sounds is degraded.
Blurry vision: 650-400 nm for visible light. Normal humans in normal light == 5mm in diameter (or a 10Kx larger hole). Divide by 300, pupil is now only 30x larger than the light waves. Scattering off the edges results in interference pattern, called diffraction - which is most noticeable when the dimensions of the object scattering the wave are comparable to the wavelength. Which is why insects have lousy vision, and different types of eyes (which adjust for diffraction effects). Or, no Ho, there would be noticeable diffraction ;)