Bridging form and meaning: Support from derivational suffixes in word learning

Background: Vocabulary development is closely associated with morphological knowledge, yet work is needed to understand the mechanisms underpinning this relationship. One possibility is that because morphological relationships entail systematic mappings between word form (phonology and orthography) and word meaning (semantics and grammar), children may take advantage of these links to form high quality lexical representations when learning novel words. This study examined whether developing readers show superior semantic, phonological, and orthographic learning of novel words when those words contain an existing suffix that is congruent with the definition of that word.
Methods: Two groups of adolescents (younger; 12-13 years; n=39, and older; 16-19 years; n=39) learned definitions for 18 nonwords, each comprising a nonword stem and an existing suffix (e.g., clantist). Half the definitions were semantically and syntactically congruent with the suffix; the other half were incongruent. Training took place across two sessions, followed by a series of post-tests measuring semantic learning (through a semantic recall task), phonological learning (through a shadowing task), lexicalisation of nonwords (through a lexical decision task) and orthographic learning (through a spelling task).
Results: Both age groups showed significantly stronger semantic recall for items taught in the congruent compared to the incongruent condition. However, this effect did not emerge in our measures of phonological and orthographic learning, or in lexicalisation of nonwords.
Conclusions: These findings provide some evidence that the presence of familiar suffixes in unfamiliar words facilitates novel word learning in adolescents, but in the present study, this benefit was only observed in the mappings between word form and meaning, and not in the learning of word forms.