In linguistics, function is usually understood to mean discriminatory function, that is, the role of the various elements of the language in the distinguishing of one sequence of sounds, such as a word or a sequence of words, from another of different meaning. Though we consider the discriminatory function to be the main linguistic function of any phonetic unit we cannot ignore the other function of phonetic units, that is, their role in the formation of syllables, words, phrases and even texts. This functional or social aspect of phonetic phenomena was first introduced in the works by I. A. Baudouin-de-Courtenay. Later on N. S. Trubetskoy declared phonology to be a linguistic science limiting articulatory and acoustic phonetics to anatomy, physiology and acoustics only.