The morpheme is one of the central notions of grammatical theory, without which no serious attempt at grammatical study can be made. Definition of a morpheme is not an easy matter, and it has been attempted many times by different scholars. Without going into particulars of the discussions that have taken place, we may briefly define the morphemes as the smallest meaningful units into which a word form may be divided. For instance, if we take the form writers, it can be divided into three morphemes: (1) writ-, expressing the basic lexical meaning of the word, (2) -er-, expressing the idea of agent performing the action indicated by the root of the verb, (3) -s, indicating number, that is, showing that more than one person of the type indicated is meant. Similarly the form advantageously can be divided into three morphemes: advantage + ous + ly, each with a special meaning of its own. Two additional remarks are necessary here: (1) Two or more morphemes may sound the same but be basically different, that is, they may be homonyms. Thus the -er morpheme indicating the doer of an action as in writer has a homonym — the morpheme -er denoting the comparative degree of adjectives and adverbs, as in longer. Which of the two homonymous morphemes is actually there in a given case can of course only be determined by examining the other morphemes in the word. Thus, the morpheme -er in our first example, writer, cannot possibly be the morpheme of the comparative degree, as the morpheme writ- to which it is joined on is not the stem of an adjective or adverb, and so no comparative degree is to be thought of here. (2) There may be zero morphemes, that is, the absence of a morpheme may indicate a certain meaning. Thus, if we compare the forms book and books, both derived from the stem book-, we may say that while books is characterised by the -s-morpheme as being a plural form, book is characterised by the zero morpheme as being a singular form. In modern descriptive linguistics the term "morpheme" has been given a somewhat different meaning.1 Scholars belonging to this trend approach the problem from this angle: If we compare the four sentences: the student comes, the students come; the ox comes, the oxen come, it will be seen that the change of student to students is 1 See, for example, H. A. Gleason Jr., An Introduction to Descriptive Linguistics, 1955, Chapter V.
Essentials of Morphology paralleled by the change of ox to oxen. That is, the meaning and function of the -en in oxen is the same as the meaning and function of the -s in students. On this account the -s and the -en are said to represent the same morpheme: each of them is a morph representing the morpheme, and they are termed allomorphs of the morpheme. Furthermore, as in the word goose the form corresponding to students and oxen is geese, where nothing is added, but the root vowel is changed, the morph representing the morpheme in this case is said to be the very change of [u:] into [i:] (graphically, oo and ее). Thus the morpheme, in this case, has three allomorphs, (1) -s, (2) -en, (3) [u:] -> [i:]. This latter item entails some difficulty, as a morph is shown not necessarily to be a material entity, that is a phoneme, or a combination of phonemes; sometimes it may be a change of one phoneme into another. Similarly, in the past tense of verbs the morpheme of the past tense has two allomorphs, (1) -ed, (2) the change of vowel, as [ai] —> [ou] (write — wrote), [i] -> [ae] (sing —sang), etc. We will apply the term "morpheme" only to material units including zero. In grammar, we are of course concerned with the grammatical, or structural, meaning of morphemes: we do not here study the meanings of root morphemes, which are necessarily lexical, and as to derivation morphemes, i. e. those which serve to build words, we are only interested in them in so far as they are grammatically relevant, and that is the case if they show that the word belongs to a certain part of speech, and if they serve to distinguish one part of speech from another. This grammatical significance of derivation morphemes, if it is there at all, is always combined with their lexical meaning. For instance, if we take this pair of words: write v. and writer n., the derivative morpheme -er has a grammatical significance, as it serves to distinguish a noun from a verb, and it has its lexical meaning, as the lexical meaning of the noun writer is different from that of the verb write. Inflection morphemes have no lexical meaning or function. There is not the slightest difference in the way of lexical meaning between live and lived, or between house and houses. However, an inflection morpheme can acquire a lexical meaning in some special cases, for instance if the plural form of a noun develops a meaning which the singular form has not; thus, the plural form colours has a meaning, 'flag', which the singular form colour has not. These are cases of lexicalisation There is in Modern English a case where a boundary line between inflection and derivation is hard to draw, and a morpheme does duty both ways. This is the morpheme -ing with its function of a suffix deriving verbal nouns and of an inflection serving to
Morphemes form a gerund, which is one of the non-finite verb forms. This appears to be quite a special case in English, and it does not seem to find any parallel in Russian.