Inflection vs. Derivation
Once you understand the difference between words and lexemes, you can understand the distinction made by morphologists between inflection and derivation.
Inflection involves the formation of grammatical forms – past, present, future; singular, plural; masculine, feminine, neuter; and so on – of a single lexeme. The use of these grammatical forms is generally dictated by sentence structure. Thus is, are, and being are examples of inflected forms of the lexeme BE, which happens to be highly irregular not only in English, but in many other languages as well. Regular verb lexemes in English have a lexical stem, which is the bare form with no affixes (e.g., select) and three more inflected forms, one each with the suffixes -s, -ed, and -ing (selects, selected, and selecting). Noun lexemes in English have a singular and plural form. Adjectives, adverbs, prepositions, and other parts of speech typically have only one form in English.
As you can tell from the example of select given above, one way inflection can be realized is through affixes. Further examples of affixal realization of inflection can be found in the following box.
Examples of words + inflectional morphemes
Nouns: wombat + s
ox + en
Verbs: brainwash + es
dig + s
escape + d
rain + ing
Derivation involves the creation of one lexeme from another, such as selector or selection from select. Compounding is a special type of derivation, since it involves the creation of one lexeme from two or more other lexemes. In the discussion of non-separability above, we had many instances of compounds (doghouse, greenhouse, hot dog, and deer tick), all of which are formed by combining two lexemes. Many processes can be involved with derivation. In the box on the next page we give only examples of affixal derivation.
One question you may be asking yourself is how we distinguish inflection from derivation. This issue is addressed fully in Inflection, but we give two criteria here: (1) derivation generally results in a change in lexical meaning or the lexical category of a particular word, while inflection does not; and (2) the application or non-application of inflectional morphology generally depends on the syntactic context (e.g., what is the subject of the verb? is the noun singular or plural?), while the application of derivational morphology does not.
Examples of words + derivational affixes
Nouns to nouns: New York + ese
fish + ery
Boston + ian
auto + biography
vice + president
Verbs to verbs: un + tie
re + surface
pre + register
under + estimate
Adjectives to adjectives: gray + ish
a + moral
sub + human
il + legible
Nouns to adjectives: hawk + ish
poison + ous
soul + ful
iron + like
Verbs to nouns: discombobulat + ion
acquitt + al
digg + er
Adjectives to adverbs: sad + ly
efficient + ly
Readers will come across the terms word formation and lexeme formation, both referring to derivation, in the morphological literature. We avoid the term word formation, since it is used by some linguists to refer to both inflection and derivation or to morphology in general.
