Knowledge of morphologically complex words: A developmental study of older children and young adolescents

Purpose: This study examined knowledge of derived nominals (e.g., measurement, prediction) and derived adjectives (e.g., algebraic, molecular) in older children and young adolescents. Little was known about students comprehension of these morphologically complex words that occur in textbooks that are used in public schools to teach challenging subjects such as science, mathematics, social studies, health, and literature. Method: The Word Knowledge Task (WKT), designed for the present study, was used to examine participants comprehension of 15 derived nominals and 15 derived adjectives that were selected from state-adopted textbooks. This written, multiple-choice task was administered to 10-year-old children and 13-year-old adolescents (N = 94) who were attending public schools. All participants spoke English and were typical achievers. Results: The findings indicated that the adolescents outperformed the children on both types of derived words; the derived nominals were more difficult than the derived adjectives for both groups; and comprehension was associated with frequency of occurrence in print, with easier words generally more common than more difficult ones. Implications: Knowledge of morphologically complex words such as derived nominals and derived adjectives is a late linguistic attainment. Given the importance of these words for academic success, instructional programs are needed to ensure that children and adolescents are able to learn their meanings using appropriate strategies.