Transcription is a useful tool used by linguists in the description of speech sounds while dealing with languages, more specifically in field studies. There have been a number of attempts to develop some systems of notation to transcribe languages as they are spoken.

In 1837 Isaac Pitman in his Stenographic Soundhand presented a system of iconic notation by using lines in various forms he tried to show the place of articulation, manner of articulation and the state of glottis. Alexander Melville Bell and his son Alexander Graham Bell developed iconic notation for teaching deaf to speak. It was only towards the end of 19th century a small group of language teachers under the leadership of Paul Passy discussed the need of having a phonetic notation to be used in the schools for learning realistic pronunciation of foreign languages. As a result The Phonetic Teachers' Association was formed in 1886. The Association proposed that the speech sounds and their production should form the basis for any account of a language system since speech is the primary form of the language. It sounded absurd and daring as it was the era of classical languages -nevertheless the proposal proved to be the foundation stone for International phonetic Alphabets.

Bernard Bloch and George L. Trager devised another notation in Outlines of Linguistic Analysis (1942).In the next year K L Pike also devised one more transcription system in Phonetics (1943) by using normal capital and lower case letters of the alphabet in Roman and Italic form.

IPA symbols are result of great amount of research and hard work. The symbols are not only users friendly but also very comprehensive, covering a wide range of speech sounds found in the languages of the world. Though the IPA has number of applications but its relevance in the field of phonetics is beyond any doubt. The IPA is based on certain theoretical assumptions such as:.

-Speech can be represented partly as a sequence of discrete sounds or 'segments'.

--Segments are classified as consonants and vowels.

--The phonetic description of segments can be made with reference to their articulatory and auditory characteristics.

The chart of International Phonetic Alphabets is arranged in terms of  tables.The table on the top of the chart shows the symbols for pulmonic consonants (the consonants pronounced with the out going air from the lungs). Since the consonants are described in terms of their place of articulation and the manner of articulation, the table is arranged accordingly. Each column represents a place for articulation starting with Bilabial to Glottal, with the exception of retroflex (it does not refer to any place of articulation). Barring fricatives, in all other categories only one symbol is given to represent Dental, Alveolar and Post-alveolar. The contrast with reference to these places in a language could be shown with the help of 'diacritics', since the chart gives another table of diacritics towards the end. At the left of the table are the rows, showing various manners of articulation such as Plosive, Nasal, Trill etc. The table refers to another important factor i.e., whether a sound is voiced or voiceless. The symbols on the left in a cell are meant for voiceless whereas the right side symbol stands for voiced.

The next two tables, placed side by side, represent non-pulmonic consonants (that make use of glottalic or velaric airstream mechanism) and vowels, respectively. The vowel symbols are represented by a four-sided figure (Vowel Quadrilateral) The vowel classification takes into account the highest point of the tongue on vertical axis (thus close, close-mid, open-mid and open), highest point of the tongue on horizontal axis (front, central and back) and the lip positions (rounded and unrounded). The vowel chart covers primary cardinal vowels as well as secondary cardinal vowels.

Besides segments, there are symbols to represent a number of suprasegmental features such as tone, stress etc. The IPA has two sets of symbols to indicate various levels of stress and tone respectively.

Diacritics are a set of symbols or marks, which can occur with various vowels and consonants to modify their original meaning or value. Some of the symbols deal with different aspects of phonation; there are diacritic marks to reverse the original value of a symbol e.g. voiceless nasals or trills(these are otherwise voiced); there are diacritic marks to show the degree of roundedness or unroundedness of lips and of height of the tongue and also to indicate secondary articulation, rhoticity and change in the manner of articulation of a consonant. In the third column the diacritics deal with the stop consonants which are released not in vowel but have nasal, lateral or no release.

The 'other symbols' chart includes the symbols which do not fit in the main table of pulmonic consonants. The sounds indicated by these symbols are rare and used in very few languages.

The shaded squares on the main chart refer to articulations that are impossible to make whereas unshaded square indicate that the sound in question is possible to produce but has not been found yet in any language.

The transcriptions could be narrow or broad, depending upon various linguistic levels of analysis and also covering the suprasegmental effects. The transcription used here is phonological, representing the pronunciation of phoneme as per its contrastive and contextual characteristics. There is one to one correlation between a sound and the symbol that represents it. A symbol, usually made up of one character such as /t/ or /i/ but sometimes of two or more as in / L /or /ts?/. The transcription here is of individual words (even when they have occurred in texts), as if one word is spoken at a time. The transcription here follows the International Phonetic Alphabet (IPA), 1996 version.

Source: David Abercrombie - Elements of General Phonetics, University Press Edinburg 1967

Handbook of the International Phonetic Association Cambridge University Press .