Letter-sound inconsistency impacts word learning and forgetting

Abstract

In alphabetic writing systems, letters and sounds have systematic mapping relations. Words that display common letter-sound relations are high in consistency (e.g., "speak," "weak"; consistent words), whereas those that use less common relations are low in consistency ("break"; inconsistent words). This study tested how letter-sound consistency affects word learning (Experiment 1) and forgetting (Experiment 2), considering various aspects of lexical knowledge, including orthography (O), phonology (P), semantics (S), and bindings between them (P-O, S-O, S-P). Eighty-six native English-speaking adults learned novel meanings for eight spoken pseudowords and then read sentences containing the written forms of these pseudowords. Half the pseudowords were consistent, whereas the other half were inconsistent. Knowledge of the pseudowords was tested immediately after learning (Experiment 1; N = 86) and with a delay (M = 77 days; Experiment 2; N = 58). Results showed that inconsistency impaired learning of most aspects of lexical knowledge (P, P-O, S-O, and S-P). After the delay, participants also showed more forgetting of P, but interestingly less forgetting of S-P, for inconsistent relative to consistent items. Together, these findings revealed that lexical development is a complex, interactive, and dynamic process. (PsycInfo Database Record (c) 2025 APA, all rights reserved).