Trubetzkoy

Prince Nikolai Sergeyevich Trubetzkoy (Russian; Moscow, April 16, 1890 - Vienna, June 25, 1938) was a Russian linguist and historian whose teachings formed a nucleus of the Prague School of structural linguistics. He is widely considered to be the founder of morphophonology.

Trubetzkoy, like other members of the Prague School, was well aware that the functions of speech are not limited to the expression of an explicit message.

A phonetic opposition which fulfils the representation function will normally be a phonetic contrast; but distinctions between the allophones of a given phoneme, where the choice is not determinated by the phonemic

environment, often play an expressive or conative role. 

A manifestation of Prague attitude that language is a tool which has a job to do the fact that members of that School were much preocupied with the aesthetic, literary aspects of language use.