Why new features?

In this chapter we continue our discussion of the phonological features that are needed in the phonology of English. Features, we noted in section 4.1, have various uses in phonological analysis. On the phonemic level of analysis, they serve to express phonemic contrast; and a good set of features would do this economically, that is, involving the smallest possible number of features. On the concrete phonetic level, features are used to provide phonetic descriptions of sounds. Moreover, features serve to define classes of phonemes required in the expression of phonological generalisations. This third function of features we have done little justice to so far; we shall discuss various kinds of generalisation, and the classes of phonemes they involve, in later chapters.

Having discussed the features that are needed to characterise the members of the basic vowel system in the preceding chapter, we now turn to the consonant phonemes. To remind ourselves of what phonemes are involved and how we have been characterising them, let us consider again table 2.2 of section 2.3.4, repeated here as table 5.1. Recall that the features used in table 5.1 are those that we used, as rather informal labels denoting phonetic properties, in our detailed description of speech sounds in chapter 1. In our exposition of the consonant phonemes of English in chapter 2, we adopted these features without discussing whether they were, in fact, the ones that we ought to be using.