The word forms that children map meanings onto may be simple or complex. So far in this book, nearly all the word forms studied have been simple nouns like dog or ball, terms with various relational meanings like uncle, top, and in, and adjectives and quantifiers like big, long, and more. These are typically simple in form, without internal structure. How do children map meanings onto complex word-forms? They must map meanings onto both roots and affixes, as well as onto combinations of roots.

The premise of this chapter is that some complex words are easier for children to map onto because their word forms are transparent in meaning or simple in form. A complex word is transparent when children know the meanings of its elements (roots and affixes), and a word is simple when the elements to be combined require either no changes or minimal changes in form. After a brief look at the mapping of meaning onto form in complex words, I take up the roles of transparency and simplicity in lexical acquisition.

Complex words

The first complex word-forms children encounter are probably not recognized as such. Established compounds like birthday and breakfast are not amenable to analysis even by adult speakers of English (Berko 1958, Derwing 1976a, 1976b). Yet by age two children show that they do attend to the separate roots in complex word-forms. For example, they offer spontaneous analyses of established compounds like lady-bug, high-chair, corn-flakes, and run-way (see Chapter 2, Table 2–1).