Derivational Morphemes

Definition of Derivational Morpheme

Before we get to the definition of derivational morphemes, let’s establish the meaning of the word derivation.

The new, derived word is related to the previous form, but it is a new word nonetheless. Many words are derived by adding a morpheme, aka a letter or a cluster of letters. A morpheme is the smallest meaningful unit of language. The key to morphemes is that they must carry some sort of significance.

So what's a derivational morpheme?

As a reminder, an affix is a letter or group of letters we attach to the beginning (prefix) or end (suffix) of a root word. Here are some of the more common affixes in the English language.

Derivational morphemes, whether prefixes or suffixes, usually change word class when added to a word (though not always).

In this example, we can see that the derivational morpheme -ful changes the noun, bounty, to the adjective, bountiful.

Derivational morphemes cannot be a word in their own right, though, because they are bound morphemes. Bound morphemes must be bound to another word or morpheme to create a word. Bound morphemes are those that can never stand alone as a word—as opposed to free morphemes, which can be independent words. A few examples of free morphemes are words such as eat, big, and ocean, while bound morphemes are affixes like -ment, im-, and -ify.

Fig 1. Bound morphemes are always tied to an existing word.

Derivational Morpheme Examples

Here are some examples of derivational morphemes:

1. "-ness" added to "kind" creates "kindness"
2. "-ment" added to "develop" creates "development"
3. "-ize" added to "modern" creates "modernize"
4. "-less" added to "hope" creates "hopeless"

As we've seen, there are many examples of derivational morphemes in the English language. Interestingly, there is no theoretical limit to how many derivational morphemes you can add to a word.

For example, think of the word "proportion". It's a noun meaning the size or shape of something relative to its whole. Add the suffix -ate, and the word is now "proportionate," referring to something that is equal in size or shape relative to its whole. But if something is not proportionate, you could add the prefix dis- to get the word "disproportionate." If you wanted to describe something that is disproportionate, you simply add the suffix -ly to get "disproportionately."

Each time we added an affix, the word changed significantly; whether changing word class, as it does when you add -ly to get an adverb, or simply negating the base word with dis- to derive disproportionate.

Inflectional vs. Derivational Morphemes

There are two types of bound morphemes: inflectional morphemes and derivational morphemes. The difference between derivational and inflectional morphemes is that inflectional morphemes signal a change in a base word’s grammatical form, e.g., its number, gender, person, or tense.

Notice how the following inflectional morphemes alter the words in each case:

An inflectional morpheme was added to each word, but it did not alter the word’s class. In other words, the nouns remained nouns (crease/ creases), the adjectives remained adjectives (nice/ nicest), and the verbs remained verbs (noticed/ noticed). Instead, the inflectional morphemes simply changed the words' form to reflect tense, aspect, number, superlative form and so on.

Fig 2. "The red house is nice, but this house is the nicest in the neighborhood." Nice and nicest are two different words with the same base.

By contrast, derivational morphemes influence the base word to such a degree that it becomes a new word entirely. That new word may, of course, be related to the original in meaning, but it is a new word nonetheless.

List of Class-Changing Derivational Morphemes

There are more instances of derivational morphemes changing the word class of the word to which they’re added. Below is a list of class-changing derivational morphemes. In these examples, the noun changes to a verb with the addition of the derivational morphemes.

Below are examples of verbs changing to adjectives with derivational morphemes:

Derivational morphemes can also change verbs to nouns (track/tracker), nouns to adjectives (boy/boyish), and so on.

Class-Maintaining Derivational Morphemes

As mentioned, derivational morphemes don’t always change the word class; those that don’t are called class-maintaining derivational morphemes. Here’s an example where the word class stays the same with the addition of a derivational morpheme:

Even though the words friend and friendship are both nouns, they are separate words with different meanings; they cannot be used interchangeably. Derivational morphemes always change either the semantic meaning of a word or the part of speech. In the case of class-maintaining derivational morphemes, only the meaning changes.

Here are some common class-maintaining derivational morphemes:

• -ship (e.g., friendship)

• Ex- (e.g., ex-cop)

• -hood (e.g., boyhood)

• Dis- (e.g., disengage)

• Un- (e.g., unlock)