Minimal pairs and beyond

The main business was the construction of rules stating allophonic distributions. These rules in turn were based on the identification of phonemes, for which we relied on the two fundamental tools of predictability of occurrence and invariance of meaning: if two sounds occur in non-overlapping, predictable sets of contexts, and if substituting one for the other does not make a semantic difference, then those two sounds must necessarily be allophones of a single phoneme. On the other hand, if those two sounds can occur in the same environments, producing different words, they belong to different phonemes. This diagnosis is confirmed by the commutation test, which involves putting different sounds in a particular context, to see if minimal pairs result. An example for English consonants is given in (1).

Accidental gaps in the English vocabulary mean that no lexical item *jat, or *lat, or *dat is available. However, minimal pairs can be found in slightly different contexts to establish, /l/, / / and so on as consonant phonemes of English: hence, we find sip zip dip tip lip, or cot dot shot jot. Considering a range of contexts provides evidence for all the consonant phonemes of English, which are plotted on a chart in (2): the voiceless labial-velar and velar fricativesand/M/and/x/ appear in brackets because they are found only in some varieties of English.

Minimal pairs and the commutation test alone will generally suffice to establish the members of a phoneme system: according to Charles Hockett, a mid-twentieth century American linguist who was very influential in the development of phoneme theory, ‘Minimal pairs are the analyst’s delight, and he seeks them whenever there is any hope of finding them’. However, there are some circumstances where phonemes cannot be established by minimal pairs alone, and we need supplementary criteria for phonemicisation, or phonological units above and beyond the phoneme. In the sections below, we turn to these special cases, and also to a consideration of the phoneme system itself, and its relevance and reality for language users.