What Are Derivational Morphemes?

Glossary of Grammatical and Rhetorical Terms

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When you're talking about biology, morphology is defined as the branch of study that deals with the form and structure of organisms and their unique structural features. Linguists often think of language as a living thing because, like a biological life form, it is reshaped by external forces acting on its structure and also changes over time. Linguistic morphology, then, is the study of how words are formed and how they relate to other words in a common language. Much the same way a biologist might study the phenomenon of metamorphosis, a linguist might study a word and its component parts to learn how its structure and meaning have evolved. In grammar, a derivational morpheme is an affix—a group of letters added before the beginning (prefix) or after the end (suffix)—of a root or base word to create a new word or a new form of an existing word.

Adding Derivational Morphemes

Adding a derivational morpheme often changes the grammatical category or part of speech of the root word to which it is added. For example, adding "ful" to the noun beauty changes the word into an adjective (beautiful), while replacing the "e" with "er" at the end of the verb merge changes it into a noun (merger). The form of a word that results from adding a derivational morpheme is known as a derived word or a derivative.

You can add derivational morphemes to free morphemes, which are those words that can't be divided into smaller component parts and retain meaning. Most one-syllable words in the English language are free morphemes. For instance, in the sentence: "I hit the man on his head," each of the words is a free morpheme that can't be broken down into smaller parts. To give the sentence a more precise meaning, I could toss in a derivational morpheme. By adding the prefix "fore" to the word "head" the reader now knows which part of the head the man was hit on. Not only does it give the precise location of the injury, it indicates a greater potential for harm since the forehead is a very sensitive part of the human anatomy.

You can also add more than one derivational morpheme to a root word to create several different meanings. For example, the verb "transform" consists of the root word "form" and a derivational morpheme, the prefix "trans." By adding the derivational morpheme "ation" as a suffix, "transform" becomes the noun "transformation." But you don't have to stop there. By adding another derivational morpheme suffix "al" after "ation," you can create the adjective "transformational."

Inflectional Morphemes vs. Derivational Morphemes

Inflectional morphemes define certain aspects pertaining to the grammatical function of a word. There are only eight inflectional morphemes in the English language—and they’re all suffixes. The two inflectional morphemes that can be added to nouns are -’s (apostrophe + s) to indicate the possessive case and -es to indicate the plural case. The four inflections that can be added to verbs are -(e)d to indicate past tense, -ing to indicate the present participle, -en, to represent the past participle, and –s, for the third person singular. The two inflections can be added to adjectives are: -er, for the comparative and -est, for the superlative.

Unlike inflectional affixes, the potential number of derivational affixes in the English language is limited only by the scope of the vocabulary of a given speaker or writer. As a result, it would impossible to create a comprehensive list of derivational morphemes but we can look at a few representative examples. In American English when suffixes such as "-ize" or "-ful" are added to a noun, the noun becomes the corresponding verb, as in cannibalize, vaporize, mesmerize, helpful, playful, thoughtful, and so on. When the suffix "-ize" is added to an adjective, the words are transformed into verbs: realize, finalize, vitalize, etc.

Some Morphemes are Both Inflectional and Derivational

Meanwhile, some inflectional morphemes, specifically -ed, -en, -er, -ing, and -ly, can take on on characteristics of derivational morphemes. For example, the suffix -er can function as both an inflectional and a derivational morpheme. In its inflectional capacity, -er is added to adjectives to indicate the comparative as in "thicker," describing something that has additional mass.

As a derivational morpheme, -er gets a lot of use in the production of forming new nouns. Such morphemes when attached to root verbs form nouns such as "farmer" to describe someone who performs the action indicated by the verb. When -er is added to a root adjective, a noun is formed: as in homesteader, which describes someone in terms of the quality denoted by the adjective. When -er is added to a nominal root noun, the meaning of the resulting noun is incorporated in the modified word. Take the word "freighter" for example. The root word "freight" has been modified, however, the definition of the new noun "freighter"—a type of vessel used to transport freight—retains the quality denoted by the original noun.


  • Hamawand, Zeki. "Morphology in English: Word Formation in Cognitive Grammar." Continuum, 2011
  • Remson, Lynne Hebert. "Oral Language" from Literacy for the New Millennium, ed. by Barbara J. Guzzetti. Praeger, 2007
  • Parker, Frank and Riley, Kathryn. Linguistics for Non-Linguists, 2nd ed. Allyn and Bacon, 1994
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Nordquist, Richard. "What Are Derivational Morphemes?" ThoughtCo, Apr. 5, 2023, thoughtco.com/derivational-morpheme-words-1690381. Nordquist, Richard. (2023, April 5). What Are Derivational Morphemes? Retrieved from https://www.thoughtco.com/derivational-morpheme-words-1690381 Nordquist, Richard. "What Are Derivational Morphemes?" ThoughtCo. https://www.thoughtco.com/derivational-morpheme-words-1690381 (accessed June 8, 2023).