dispersion (n.)

In PHONETICS, a term used to refer to the location of CONTRASTIVE elements within a phonetic domain (such as the VOWEL SYSTEM or TONE system), as part of the comparative study of the size and character of phonetic inventories. Sounds tend to maximize the available ARTICULATORY space so as to be as different as possible from each other. For example, if a language has a three-vowel system, a principle of maximal dispersion would predict that the vowels would be those furthest away from each other in terms of the BACK–front and HIGH–low dimensions: /i/, /a/, and /u/. In a language with more vowels, the ‘extra’ vowels would position themselves at intermediate points.

Other factors have to be recognized to handle systems which do not work with their elements separated in such a symmetrical way.