Noises, also, can often be classed roughly as higher or lower in pitch, as when we assert that the sound of a hammer hitting a nail is higher in pitch than the sound of surf booming along a beach.
- Hockett (1958), a pag.113

The communicative importance of redundancy is that errors of transmission collectively called ‘noise’ in information theory are inevitable; a certain amount of redundancy prevents this inevitable measure of noise from destroying communication altogether.
- Hockett (1958), a pag.88-89