As it was shown in § 16 Morphology includes several types of units and two types of grammatical meanings which employ the units as their forms. Besides connection with grammatical meanings the units have syntagmatic and paradigmatic properties. Because the units might be in different relations, and, besides, they might reflect different meanings, they might be of different types. Details of the types of units of morphology will be discussed in the chapter dealing with general features of word later. Now it is necessary to indicate the principles which may differentiate unites of the same class.
Forms of words might differ, first of all, in the number of categorial forms they express the difference might be from one to as many categorial forms, as the word may have categories. Word forms are composed of morphemes which, in their turn, are represented by morphs. And here we may find certain discrepancies between paradigmatic and syntagmatic properties of morphs. Some morphs remain elements of a word form both in the paradigmatic and syntagmatic spheres. Some morphs must be treated as morphs paradigmatically and at the same time, as a separate unit syntagmatically. This fact may produce different types of forms of words.
Morphemes, besides, might differ in the number of morphs they use for their representation in speech. We may find morphemes having no morphs whatsoever to represent them as we see in the singular number form “hand”.
Morphs also differ in the ability to represent different morphemes. There are morphs representing only one morpheme as |ing|, but we may find morphs that are representations of several morphemes as |z|, which as used by the morpheme of the third person singular present indicative and plural of nouns and the possessive case of nouns.
Categories differ in the number of category forms included into their oppositions. They may also be different in the manner of oppositions themselves (see §11).