Inflection Definition and Examples in English Grammar

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Inflection refers to a process of word formation in which items are added to the base form of a word to express grammatical meanings. The word inflection comes from the Latin inflectere, meaning "to bend."

Inflections in English grammar include the genitive 's; the plural -s; the third-person singular -s; the past tense -d, -ed, or -t; the negative particle 'nt; -ing forms of verbs; the comparative -er; and the superlative -est.

While inflections take a variety of forms, they are most often prefixes or suffixes. They are used to express different grammatical categories. For example, the inflection -s at the end of dogs shows that the noun is plural. The same inflection -s at the end of runs shows that the subject is in the third person singular (s/he runs). The inflection -ed is often used to indicate the past tense, changing walk to walked and listen to listened. In this way, inflections are used to show grammatical categories such as tenseperson, and number.

Inflections can also be used to indicate a word's part of speech. The prefix en-, for example, transforms the noun gulf into the verb engulf. The suffix -er transforms the verb read into the noun reader.

In "The Frameworks of English," Kim Ballard writes that

When considering inflections, it can ... be helpful to use the notion of a stem. A stem is what remains of a word when any inflections are removed from it. In other words, inflections are added to the stem of a word. So frogs is made up of the stem frog and the inflection -s, while turned is made up of the stem turn and the inflection -ed.

Inflection Rules

English words follow different rules for inflection based on their part of speech and grammatical category. The most common rules are listed below.

Part of SpeechGrammatical CategoryInflectionExamples
NounNumber-s, -es

Flower → Flowers

Glass → Glasses

Noun, PronounCase (Genitive)-'s, -', -s

Paul → Paul's

Francis → Francis'

It → Its

PronounCase (Reflexive)-self, -selves

Him → Himself

Them → Themselves

VerbAspect (Progressive)-ingRun → Running
VerbAspect (Perfect)-en, -ed

Fall → (Has) fallen

Finish → (Has) finished

VerbTense (Past)-edOpen → Opened
VerbTense (Present)-sOpen → Opens
AdjectiveDegree of Comparison (Comparative)-erSmart → Smarter


Degree of Comparison (Superlative)-est

Smart → Smartest


Not all English words follow the rules in this table. Some are inflected using sound changes known as vowel alternations, the most common of which are ablauts and umlauts. The word "teach," for example, is marked as past tense by changing its vowel sound, producing the word "taught" (rather than "teached"). Likewise, the word "goose" is pluralized by changing its vowel sound to produce the word "geese." Other irregular plurals include words like "oxen," "children," and "teeth."

Some words, such as "must" and "ought," are never inflected at all, no matter the context in which they appear. These words are considered invariant. Many animal nouns share the same singular and plural forms, including "bison," "deer," "moose," "salmon," "sheep," "shrimp," and "squid."

The inflection of English verbs is also known as conjugation. Regular verbs follow the rules listed above and consist of three parts: the base verb (present tense), the base verb plus -ed (simple past tense), and the base verb plus -ed (past participle). For example, following these rules, the verb "look" (as in, "I look around the room") becomes, in both the simple past tense and the past participle, "looked" ("I looked around the room," "I have looked around the room").

While most verbs follow these conjugation rules, there are over 200 words in the English language that do not. These irregular verbs include be, begin, bid, bleed, catch, deal, drive, eat, feel, find, forget, go, grow, hang, have, hide, leave, lose, meet, pay, prove, ride, ring, seek, send, shall, shine, show, sing, spin, steal, take, tear, wear, and win. Since these words do not follow the rules for most English verbs, their unique conjugations must be learned on their own.


  • S. Greenbaum, The Oxford English Grammar. Oxford University Press, 1996
  • R. Carter and M. McCarthy, Cambridge Grammar of English. Cambridge University Press, 2006
  • Kim Ballard, The Frameworks of English: Introducing Language Structures, 3rd ed. Palgrave Macmillan, 2013
  • A. C. Baugh, A History of the English Language, 1978
  • Simon Horobin, How English Became English. Oxford University Press, 2016