Familiarity and transparency in idiom explanation: a developmental study of children and adolescents.

Idioms differ widely in their degree of difficulty for children and adolescents. Two factors that might account for these differences, familiarity and transparency, were examined. Children and adolescents ages 11, 14, and 17 years (N = 150) were asked to explain in writing the meanings of 24 different idiomatic expressions, each presented in a brief story context. Results showed that performance on the task gradually improved as subject age increased and that high-familiarity idioms were generally easier to explain than moderate- or low-familiarity expressions. Easier idioms also tended to be more transparent. The results are consistent with the "language experience" view of figurative development and question the hypothesis that idioms are learned as giant lexical units.