Word formation refers to the ways in which new words are created on the basis of other words and how they become part of the language. Most of the time this is done by means of suffixes, e.g. -ment, -ion (with nouns) and -ive, -ing (with adjectives). For instance: with a root such as the verb "to attract" you can create the noun "attraction" and the adjective "attractive". Understanding word formation can help you understand the English language better.