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, 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-. 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.
- Headword (lemma)
- Hirsh, D.; Nation, I.S.P. (1992). "What vocabulary size is needed to read unsimplified texts for pleasure?" (PDF). Reading in a Foreign Language. 8 (2): 689–696.
- Bauer, L.; Nation, I.S.P. (1993). "Word families". International Journal of Lexicography. 6 (4): 253–279. doi:10.1093/ijl/6.4.253.