When we add -ed to walk, or change mouse to mice, this change of morphology produces an inflection (‘bending’) of the basic word which has special grammar (e.g. past tense or plural). In contrast, adding -er to walk produces a completely different word, walker, which is part of the same word family. Inflection is sometimes thought of as merely a change of ending, but, in fact, some words change completely when inflected.
- dogs is an inflection of dog.
- went is an inflection of go.
- better is an inflection of good.
An inflection is a change to the base form of a word to express grammatical information, usually by adding an ending (or suffix). Sometimes inflection involves another kind of change to the base form (e.g. mouse/mice).