A suffix is a bound morpheme attached to the end of a root or stem to create a new form or to mark a grammatical relationship. Suffixes are one type of affix and appear in many languages. They can change a word’s part of speech, indicate tense, number, degree, or produce derived vocabulary such as agent nouns and abstract nouns.

Types and common examples

Suffixes are often classified as either inflectional or derivational:

  • Inflectional suffixes modify grammatical features without creating a new lexeme. English examples include -s (plural: cats), -ed (past tense: walked), -ing (progressive: running), and comparative/superlative -er/-est (taller, tallest).
  • Derivational suffixes form new words and often change word class: -er (agent: teach → teacher), -ness (state: happy → happiness), -able (capability: read → readable), -tion/-ment (nominalization: act → action, govern → government).

Spelling and form changes

Adding a suffix can trigger orthographic adjustments: dropping a final -e (make → making), doubling a consonant (run → running), or changing y to i (happy → happiness). Languages differ in how productive particular suffixes are — some allow many new coinages, others are restricted by phonology or meaning.

History and linguistic role

Suffixation is an ancient and widespread morphological process. In Indo-European languages many common suffixes derive from older bound particles and case endings. Over time, suffixes have evolved into markers of tense, aspect, voice, or to create lexical families that help speakers recognize related concepts.

Uses, importance and distinctions

Suffixes are central to word formation, grammar teaching, and vocabulary expansion. They differ from prefixes, which attach to the beginning of a word; for a comparison see prefixes. Understanding suffix patterns aids reading, spelling, and morphological analysis. For more on adjectives and how their endings work see adjectives.

Notable facts: some languages mainly use suffixes (agglutinative languages), while others rely more on word order or separate function words. Recognizing suffixes also helps in etymology and in learning related languages through shared morphological patterns.