2.1 Examine the concepts of Distinctive and Non-Distinctive Variation in the context of phonology
Distinctive And Non-Distinctive Variation:
In linguistics, a distinctive feature is the most basic unit of phonological structure that may be analyzed in phonological theory. Distinctive features are grouped into categories according to the natural classes of segments they describe: major class features, laryngeal features, manner features, and place features. On the other hand Non-distinctive features are identical phonemes, no different meanings, but just allophones. The allophones are predictable, redundant, non-distinctive, and non-phonemic. bean/bead – the nasality feature occur before syllable-word-final nasal consonants.
It is often said that English has 44 vowel and consonant sounds: 20 vowel sounds (including diphthongs) 24 consonants sounds
Such a statement ignores an infinite number of different “shades” of sound. Each vowel or consonant varies slightly in pronunciation according to its position in words or phases and under the influence of neighboring sounds. Except in a very detailed phonetic study, most if these “shades” of variation can be ignored for practical purposes because they are non-distinctive. That is, they make no difference to the meaning of the word sentence.
a. An English /t/ is usually articulated with the tip of the tongue on the alveolar ridge, as in /tǽp/ or /put/. But if the next sound is dental (pronounced on the teeth), a mechanical assimilation takes place so that the /t/ will also be articulated on the teeth, as in /witθ/.
b. An English plosive, for instance /p/, is normally followed by an explosive of air from the mouth. But when another plosive follows it or a nasal consonant, this explosion of air does not usually happen. For example, in /ki” p mi”/, there is no explosion of the /p/.
In our phonetic script, we are ignoring such shades of sound, writing just /t/ or /p/ in each case. That is to say that our phonetic script for English is a “phonemic” one. It recognizes only those differences of sound, which are distinctive in English. The differences between alveolar and dental /t/ between exploded and unexploded /p/ is non-distinctive since it can never, in English, make a difference in the meaning of a word.
But of course the difference between /t/ and /p/, or between /t/ and /s/, is distinctive in English. The first difference would turn /tik/ (“tick”) into /pik/ (“pick”) and the second difference would turn /ti: m/ (team”) into /si: m/ “seem”). Therefore /t/ (whatever its exact “shade”) must be kept clearly distinct in out speech or we shall not be understood.
We say that /t/, /p/ and /s/ are three of the distinctive “phonemes” (sound-classes) of English. The technical theory of the phoneme will not concern us here (and in fact the account given above is slightly over-simplified). For present purposes you need only a practical grasp of the subject. You should understand, for instance, that an alveolar and a dental /t/ are just two possible pronunciations of the same English “phoneme”. We ignore the difference in our “phonemic” transcriptions and just write “/t/” got both.
In this sense, we should not say that English has “sounds” (for in fact it has an infinite number, each of which could be given a different IPA symbol), but rather that it has 44 distinct “phonemes”, each realized in slightly different ways in different contexts.