Inflection is a one of the main types of morphological operations by which an affix is added to a word. An inflectional affix adds a particular grammatical function to a word without changing the category of that word, or even leading to a different word. We may say that inflected forms are just variants of one and the same word. Some examples of grammatical information that can be encoded by inflectional morphemes include Phi-features (e.g. person, number, gender, case), mood, tense, and aspect.
The relational adjective is inflectional. An alternative spelling (confined to British English and increasingly outdated) is inflexion.
Count nouns in English can be pluralized by adding the inflectional ending -s (dog-dogs, noun-nouns). The plural forms dogs and nouns are variants of the base nouns dog and noun.
Traditionally inflection is distinguished from derivation (the second type of major morphological operation). Although it is not possible to draw a sharp boundary between both types of operation, there are at least two differences: (i) inflection is never category-changing, while derivation often category changing, and (ii) inflection is usually peripheral to derivation. Some linguists (e.g. Aronoff (1976), Anderson (1982), Perlmutter (1988)) assume that inflection and derivation belong to different components of the grammar. This view is not uncontroversial though, since others (e.g. Halle (1973), Kiparsky (1982)) assume that inflection and derivation are reflexes of one and the same operation, namely affixation.
- Anderson, S.R. 1982. Where's Morphology?, Linguistic Inquiry 13, pp. 571-612, MIT Press, Cambridge, Mass.
- Aronoff, M. 1976. Word Formation in Generative Grammar, MIT-press, Cambridge, Mass.
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- Halle, M. 1973. Prolegomena to a Theory of Word-Formation, Linguistic Inquiry 4, pp. 451-464
- Haspelmath, M. and A. Sims. 2010. "Chapter 5: Inflection and Derivation" in Understanding Mophology Second edition. Routledge.
- Kiparsky, P. 1982. From Cyclic Phonology to Lexical Phonology, in: Hulst, H. van der and N. Smith (eds.) The Structure of Phonological Representations (I), pp.131-175
- Perlmutter, D. 1988. The Split-morphology Hypothesis: evidence from Yiddish, in: Hammond, M. and M. Noonan (eds.) Theoretical Morphology: Approaches in Modern Linguistics, Orlando, Academic Press.
- Pollock, J.-Y. 1989. Verb movement, Universal Grammar, and the structure of IP, Linguistic Inquiry 20, pp.365-424.