Word family

A word family is the base form of a word plus its inflected forms and derived forms made with suffixes and prefixes^[1] plus its cognates, i.e. all words that have a common etymological origin, some of which even native speakers don't recognize as being related (e.g. "wrought (iron)" and "work(ed)").^[2] In the English language, inflectional affixes include third person -s, verbal -ed and -ing, plural -s, possessive -s, comparative -er and superlative -est. Derivational affixes include -able, -er, -ish, -less, -ly, -ness, -th, -y, non-, un-, -al, -ation, -ess, -ful, -ism, -ist, -ity, -ize/-ise, -ment, in-.^[1] The idea is that a base word and its inflected forms support the same core meaning, and can be considered learned words if a learner knows both the base word and the affix. Bauer and Nation proposed seven levels of affixes based on their frequency in English.^[3] It has been shown that word families can assist with deriving related words via affixes, along with decreasing the time needed to derive and recognize such words.^[4]