Structural types of words. The morphological analysis of word- structure on the morphemic level aims at splitting the word into its constituent morphemes – the basic units at this level of analysis – and at determining their number and types.
The four types (root words, derived words, compound, shortenings) represent the main structural types of Modern English words, and conversion, derivation and composition the most productive ways of word building. According to the number of morphemes words can be classified into monomorphic and polymorphic. Monomorphic or root-words consist of only one root-morpheme, e.g. small, dog, make, give, etc. All polymorphic word fall into two subgroups: derived words and compound words – according to the number of root-morphemes they have. Derived words are composed of one root-morpheme and one or more derivational morphemes, e.g. acceptable, outdo, disagreeable, etc. Compound words are those which contain at least two root-morphemes, the number of derivational morphemes being insignificant.
There can be both root- and derivational morphemes in compounds as in pen-holder, light-mindedness, or only root-morphemes as in lamp-shade, eye-ball, etc. These structural types are not of equal importance.
The clue to the correct understanding of their comparative value lies in a careful consideration of: 1)the importance of each type in the existing wordstock, and 2) their frequency value in actual speech. Frequency is by far the most important factor. According to the available word counts made in different parts of speech, we find that derived words numerically constitute the largest class of words in the existing wordstock; derived nouns comprise approximately 67% of the total number, adjectives about 86%, whereas compound nouns make about 15% and adjectives about 4%. Root words come to 18% in nouns, i.e. a trifle more than the number of compound words; adjectives root words come to approximately 12%. But we cannot fail to perceive that root-words occupy a predominant place.
In English, according to the recent frequency counts, about 60% of the total number of nouns and 62% of the total number of adjectives in current use are root-words.
Of the total number of adjectives and nouns, derived words comprise about 38% and 37% respectively while compound words comprise an insignificant 2% in nouns and 0.2% in adjectives. Thus it is the root-words that constitute the foundation and the backbone of the vocabulary and that are of paramount importance in speech. It should also be mentioned that root words are characterized by a high degree of collocability and a complex variety of meanings in contrast with words of other structural types whose semantic structures are much poorer.
Root- words also serve as parent forms for all types of derived and compound words. III.