Why do ducks make funny sounds?

To a duck, YOU make funny noises!

What a voice sounds like is a result of the equipment used to make it. A duck's vocal chords are quite different from those of a human or a cow or a robin. Therefore it produces different sounds.

The duck language is quite interesting. Gestures, inflections and voice intensity all are part of how they communicate with each other. I've been studying them for four years and I'm just getting a handle on it.