Which morphological skills predict development in vocabulary? Contrasting morphological awareness with morphological analysis

Morphemes are the smallest units of meaning in language. This study examined which of two related morphological skills support vocabulary growth: morphological awareness (recognizing and manipulating morphemes) and morphological analysis (using morphemes to infer meanings). We studied 336 English-speaking children (F = 154, M = 182; Mage = 6 years and 8 months; 55% European, with <10% each Acadian, Asian, African, Aboriginal, and Middle Eastern). In Grade 1, children completed morphological awareness and analysis tasks, and controls of reading comprehension, word identification, phonological awareness, nonverbal ability, and working memory. Vocabulary was measured at Grades 1 and 4. Structural equation modeling revealed that only morphological analysis uniquely predicted gains in vocabulary.