Morphology is an area of linguistics that focuses on words. The morpheme is the basic unit of morphology, and morphology is divided into two branches: inflectional and derivational. The other main branch of morphology is syntax—the study of sentences.
Inflectional morphology is a change in word form. This usually means the use of endings. He works, he worked, and he is working shows the use of different endings to represent simple present, simple past, and present continuous forms. The -s, -ed, and -ing are affixes. In this example, words are inflected to show verb forms. Inflection is also used for plural forms: book, books. In addition, inflection is used to show noun case (student, student's, students') and the comparative and superlative forms of adjectives (soft, softer, softest).
Derivational morphology creates new words. For example, beauty becomes beautiful. The affix -ful changes the word from a noun to an adjective. Another example is changing teach into teacher; the -er changes it from a verb into a noun. The suffix -ize can be attached to a noun to create a verb: critic, criticize. Derivational morphology uses many more affixes than inflectional morphology.