Psychological (Mentalistic) view regards the phoneme as an ideal “mental image” at which the speaker aims. The originator of the theory, I.A. Baudauin de Courtenay viewed phonemes as fictitious units and considered them to be only perceptions. The theory has been adopted by American structuralists E.D. Sapir and L.B. Bloomfield, who defined phoneme as a minimum unit of distinctive-sound features, an abstractional fiction.
Functionalview regards the phoneme as the minimal sound unit by which meanings may be differentiated without much regard to actually pronounced speech sounds. This view is shared by L.B. Bloomfield, R. Jackobson, M. Halle Different opinions in the nature of phoneme and N.S. Trubetskoy, representative of the Prague linguistic school, who defined the phoneme as a unity of phonologically relevant features.
Abstractview of the phoneme regards phonemes as essentially independent of the acoustic and physiological properties associated with them, that is, of speech sounds. This view of the phoneme was pioneered by L. Hjelmslev and his associates in the Copenhagen Linguistic Circle, H. J. Uldall and K. Togby.
The physical view regards the phoneme as a “family” of related sounds satisfying certain conditions. The view was introduced by D. Jones representative of the London School of Different opinions in the nature of phoneme phonology, who defined phonemes as a family of sounds. The view was shared by B. Bloch and G. Trager. Representative of the French linguistic school Ferdinand de Saussure viewed phonemes as the sum of acoustic impressions and articulatory movements.
Transcription is a set of symbols representing speech sounds. The symbolization of sounds differs according to whether the aim is to indicate the phoneme or to reflect the modifications of its allophones.
I. The Broad or phonemic transcription provides special symbols for all the phonemes of a language and mainly used for practical purposes.
Phonemic transcription is based on the principle Different opinions in the nature of phoneme “one symbol per phoneme”. A phoneme is reflected in this transcription as an abstraction and generalization. The symbols are usually placed between two slanting lines: /p/, /b/, /i/, /u: / etc.
II. The Narrow or allophonic transcription is based on the principle “one symbol per allophone”. This transcription provides a special sign for each variant of each phoneme (diacritics): [khit]. A phoneme is reflected in this transcription as a unity of all its allophones. The symbols are usually placed between square brackets [ ]. The narrow type serves the purposes of research work.