With the aid of examples, distinguish between inflectional morphemes and derivational morphemes.

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Inflectional morphemes are words that are created from a lexeme, or a basic unit of meaning in a language, without creating a new category in one's lexicon. An example of an inflectional morpheme is "books," which is created from the word "book." The new word that is created is in the same grammatical category as the original word (in the case of "book" and "books," both are nouns). Other inflectional affixes (affixes are added to the root of a word) change the word with regard to tense, case, and gender, such as "brings" from "bring" (changing tenses); "Mary's" from "Mary," (changing cases); or "masseur" from "masseuse" (changing gender). 

On the other hand, derivational morphemes are words that have different lexemes from the original word. A derivational affix can produce a word that's in a different grammatical category from the original word. For example, adding "ly" to the word "quick" changes the grammatical category of the word "quick" (as "quick" is an adjective, and "quickly" is an adverb). In addition, a derivational morpheme can have a very different meaning than the original word. For example, if you add "non" to "sense," you produce the word "nonsense," which is in the same grammatical category as the first word (both are nouns). However, "nonsense" has a very different meaning than the word "sense." If an affix changes the part of speech of the word or the meaning of the word, it is a derivational affix.