1.2.3 Morphological criteria for determining category

The first two cases in (13) represent the regular plural form in English, as we have been discussing. But even here there are differences. In the first case the morpheme is pronounced [z] whereas in the second it is pronounced [s]. This is a fact about English morpho-phonemics, that certain morphemes are unvoiced following an unvoiced consonant, that we will not go into in this book. However, this does show that what we are dealing with is something more abstract than simply pronunciations. This point is made even more forcefully by the third and fourth cases. The plural form men differs from the singular man in terms of the quality of the vowel and the plural form sheep is phonetically identical to the singular form sheep. From our point of view, however, the important point is not the question of how morphological forms are realised (that is a matter for phonologists), but that the morphological forms exist. Sheep IS the plural form of sheep and so there is a morphological plural for this word, which we know therefore is a noun. There is no plural form for the word warm, even abstractly, and so we know that this is not a noun.