You have now seen a number of symbols of several different sorts. Basically the symbols are for one of two purposes: either they are symbols for phonemes (phonemic symbols) or they are phonetic symbols (which is what the symbols were first introduced as).

We will look first at phonemic symbols. The most important point to remember is the rather obvious-seeming fact that the number of phonemic symbols must be exactly the same as the number of phonemes we decide exist in the language. It is rather like typing on a keyboard - there is a fixed number of keys that you can press. However, some of our phonemic symbols consist of two characters; for example, we usually treat ʧ (as in 'chip' ʧɪp) as one phoneme, so ʧ is a phonemic symbol consisting of two characters (t and ʃ).

One of the traditional exercises in pronunciation teaching by phonetic methods is that of phonemic transcription, where every speech sound must be identified as one of the phonemes and written with the appropriate symbol. There are two different kinds of transcription exercise: in one, transcription from dictation, the student must listen to a person, or a recording, and write down what they hear; in the other, transcription from a written text, the student is given a passage written in orthography and must use phonemic symbols to represent how she or he thinks it would be pronounced by a speaker of a particular accent. In a phonemic transcription, then, only the phonemic symbols may be used; this has the advantage that it is comparatively quick and easy to learn to use it. The disadvantage is that as you continue to learn more about phonetics you become able to hear a lot of sound differences that you were not aware of before, and students at this stage find it frustrating not to be able to write down more detailed information. The phonemic system described here for the BBC accent contains forty-four phonemes. We can display the complete set of these phonemes by the usual classificatory methods used by most phoneticians; the vowels and diphthongs can be located in the vowel quadrilateral - and the consonants can be placed in a chart or table according to place of articulation, manner of articulation and voicing. Human beings can make many more sounds than these, and phoneticians use a much larger set of symbols when they are trying to represent sounds more accurately. The best- known set of symbols is that of the International Phonetic Association's alphabet (the letters IPA are used to refer to the Association and also to its alphabet). The vowel symbols of the cardinal vowel system (plus a few others) are usually included on the chart of this alphabet, which is reproduced at the beginning (p. xii). It is important to note that in addition to the many symbols on the chart there are a lot of diacritics - marks which modify the symbol in some way; for example, the symbol for cardinal vowel no. 4 [a] may be modified by putting two dots above it. This centralization diacritic then gives us the symbol [ä] for a vowel which is nearer to central than [a]. It would not be possible in this course to teach you to use all these symbols and diacritics, but someone who did know them all could write a transcription that was much more accurate in phonetic detail, and contained much more information than a phonemic transcription. Such a transcription would be called a phonetic transcription; a phonetic transcription containing a lot of information about the exact quality of the sounds would be called a narrow phonetic transcription, while one which only included a little more information than a phonemic transcription would be called a broad phonetic transcription. One further type of transcription is one which is basically phonemic, but contains additional symbolic information about allophones of particular symbols: this is often called an allophonic transcription. As an example of the use of allophonic transcription, in this course phonetic symbols are used occasionally when it is necessary to give an accurate label to an allophone of some English phoneme, but we do not do any phonetic transcription of continuous speech: that is a rather specialized exercise. A widely-used convention is to enclose symbols within brackets that show whether they are phonemic or phonetic: when symbols are used to represent precise phonetic values, rather than phonemes, they are often enclosed in square brackets [ ], as we have done already with cardinal vowels; in many phonetics books, phonemic symbols are enclosed within slant brackets / /. While this convention is useful when giving a few examples, there is so much transcription that I feel it would be an unnecessary distraction to enclose each example in brackets. We will continue to use square brackets for cardinal vowel symbols, but elsewhere all symbols are printed in blue type, and the context should make it clear whether the symbols are phonemic or phonetic in function.

It should now be clear that there is a fundamental difference between phonemic symbols and phonetic symbols. Since the phonemic symbols do not have to indicate precise phonetic quality, it is possible to choose among several possible symbols to represent a particular phoneme; this has had the unfortunate result that different books on English pronunciation have used different symbols, causing quite a lot of confusion to students. In this course we are using the symbols now most frequently used in British publishing. It would be too long a task to examine other writers' symbols in detail, but it is worth considering some of the reasons for the differences. One factor is the complication and expense of using special symbols which create problems in typing and printing; it could, for example, be argued that a is a symbol that is found in practically all typefaces whereas æ is unusual, and that the a symbol should be used for the vowel in 'cat' instead of æ. Some writers have concentrated on producing a set of phonemic symbols that need the minimum number of special or non-standard symbols. Others have thought it important that the symbols should be as close as possible to the symbols that a phonetician would choose to give a precise indication of sound quality. To use the same example again, referring to the vowel in 'cat', it could be argued that if the vowel is noticeably closer than cardinal vowel no. 4 [a], it is more suitable to use the symbol {, which is usually used to represent a vowel between open-mid and open. There can be disagreements about the most important characteristics of a sound that a symbol should indicate: one example is the vowels of the words 'bit' and 'beat'. Some writers have claimed that the most important difference between them is that the former is short and the latter long, and transcribed the former with i and the latter with i: (the difference being entirely in the length mark); other writers have said that the length (or quantity) difference is less important than the quality difference, and transcribe the vowel of 'bit' with the symbol I and that of 'beat' with i. Yet another point of view is that quality and quantity are both important and should both be indicated; this point of view results in a transcription using I for 'bit' and i:, a symbol different from ɪ both in shape of symbol (suggesting quality difference) and in length mark (indicating quantity difference), for 'beat'. This is the approach taken in this course.