What is "word family"

A word family is the base form of a word plus its inflected forms and derived forms made from affixes . In the English language, inflectional affixes include third person -s, -ed, -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- . 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.