The present SAMPA system, which was provisionally agreed at the end of the Extension Phase, is defined as a system for phonemic transcription and annotation. This means that the symbols are used according to the analysis of distinctive sound oppositions within each language. Thus, although their relation to sound category symbols of the International Phonetic Alphabet (IPA) is given, they are symbols of intra-language convention, and do not have an exact language-independent phonetic (auditory or acoustic) equivalence, nor do they represent a single sound within a language.
For example, the symbol /t/, used in the transcription of all 8 partner languages, could represent an unaspirated sound in French or Italian, a strongly aspirated sound in German or English, and an affricated sound in Danish. In English the /t/ can also stand for an unaspirated sound (following /s/) or the more usual aspirated sound. Vowel symbols often represent widely diverging sounds from one language to another; /{/ in Danish is very different from /{/ in English, for example.
This basically phonemic, or sound-system-orientated (systematic) function of SAMPA means that a general extension of the SAMPA coding system to allow fine phonetic differentiation of speech sounds is not possible. There are, however, examples in the SAMPA list of symbols which can be used to represent non-distinctive differences within a language, e.g. ``r'' and ``R'' for regionally dependent free variants, and some important allophonic variants are allowed for (e.g. in Swedish and Norwegian). Also, auditory transcription (French ``notation'') is meant to be a ``broad phonetic'' representation of the actual utterance, including elisions and assimilations (inasfar as these can be represented with the phonemically orientated SAMPA inventory) rather than the strictly phonemic string of the citation form.
One area in which an extension of SAMPA is possible, indeed probable, is prosody. Certain ``Boundary and Prosodic Features'' have been agreed preliminarily, but their use has only been illustrated in the English EUROM-0 transcriptions. The considerations of prosodic description in a multilingual context may well reveal the need to modify and extend SAMPA. The work on prosodic description may also conclude that a separate prosodic annotation tier is necessary.