When we use the 44 symbols of vowels and consonants we are dealing with the phonemic transcription which is also called abstract and broad transcription; but if we add details to such a transcription, we are dealing with the phonetic transcription which is known to be concrete and narrow. The symbols used to indicate details are called diacritics, the new phoneme is called allophone (a variant of the phoneme in the detailed transcription): [ ph ]is an allophone to of /p/ in a given situation (when /p/ is in initial stressed syllable). What follows are example of some variants of phonemes occurring in different environments:
1. Shortening of vowels before voiceless consonants:
- Neat [ nit ] the vowel is fully shortened
- Need [ni.d ]the vowel is slightly shortened
- Knee [ni: ] the vowel is fully long
This is the way length of vowel is diacritically represented. We use a different diacritic with short vowels and diphthongs:
- Bit [bit] Coat ['jut ]
Note: when the vowel is shortened, the following consonant is long. For example, in `bit' theT is made longer by pronouncing a schwa after it: [bit]
- Aspiration of /p, t, Id when they are initial in stressed syllables After the release of plosives, there is a short breath or a moment of noiselessness before the start of the voicing of the vowel. The voiceless period is called aspiration and it is represented by 'h'. In fact, what really happens is the fact that voiceless consonants cause vowels to lose part of their vticing; the voicing is replaced by a short breath.
a Pool [1)1'111 ]
- Devoicing of /b, d, g/ in initial and final positions
They become partly voiceless. In these cases, they are confused with /p, t, k/ but the difference is felt in the length of the vowels: vowels are shortened before voiceless /p, t, k/ than before /b, d, g/ which in turn are made longer.
- Bid [bid] did [did] big [big]
4. Devoicing of /j, w, r, 1/ after /p,t,k/
When there is devoicing, there is a manifestation of aspiration.
- Pure [pju-i] cure [ kjuo] twice [twais] pray [prei]
5. Nasalization of vowels before nasals Air goes out through the nasal cavity:
- Uncle [2,'-jkl] lamp
6. Neutralisation of /t, d/ between vowels before unstressed syllables: They can be replaced by a sound called `tap' or 'flap'. The symbol to it is `r.' or 'ID':
- Better [Iva)] body [ bib Di]
7. Velarisation of /1/ before plosives and after vowels In this case /1/ is no longer alveolar, but velar
- Tall [t ,-4-] gold [giu-l-d]
8. Dentalisation of stops, nasals and laterals before dental fricative
In this case, these sounds are articulated with the tip of the tongue between upper and lower teeth.
- Tenth [ten( ] wealth [weir.] width [wid
9. Inaudible plosives before other stops or at the end of words
A full articulation of plosives goes through three stages: closure-hold-release. But when a plosive is followed by another plosive, the third stage can be absent at the end of the first plosive, so, air is not released and the sound is not audible (heard). This can happen, too, when the plosive is at the end:
- Apt [ *fit] night [nait-1]
110. Glot,.:aLsation of /p,t.„.k/
A glottal stop is a sound that occurs when the vocal cords are tightly closed then suddenly open. The symbol to it is [ ]. The glottal stop often occurs as an allophone to /t/. Most Americans and many British speakers have a glottal stop followed by a syllabic nasal:
- 4* Beaten [bi: i'n] kitten [kii'n] fatten [fa: in]
London Cockney has a glottal stop between vowels:
- Butter [bA ,)] fatter [fa: .)]
Many speakers of both countries have a glottal stop before final voiceless stops:
- Rap [ r z 4] rat [ r r-t] rack [ ri, i1 k]
Note: The voiceless stop can be glottalised and inaudible in the same time, glottalised and audible, or inaudible without a glottal stop, or neither glottalised nor inaudible.
11. Syllabic consonants
A consonant (mostly '1' and 'n') can occupy the place of the weak vowel "mainly at the end of words. In this case we say that schwa is omitted:
- Seven [sevn] bottle [botl ] police [plis]