To determine whether second-language learners encode vocabulary in memory by families of associated meanings and/or interrelated sounds (acoustic and semantic encoding clusters), and to ascertain the correlation between such encoding and language proficiency, 75 students were administered tests of STM vocabulary recognition and language proficiency. In experiment 1, 59 Ss were selected from 5 groups: 1 native speaker group and a group from each of the 4 proficiency levels for foreign students studying English as a second language. In a second study to cross-validate the experiment, 16 native speakers and students of Persian as a second language were tested.
Results indicated that second-language learners do encode vocabulary into acoustic and semantic memory clusters; semantic and acoustic recognition errors were significantly more frequent than nonrelated errors (p < .01). Learners at a low-proficiency level appeared to register vocabulary in memory more by sound similarities than by related meanings; high-proficiency learners relied on associated meanings rather than sound similarities. Significant positive correlations (r= .612, .675) were found between proficiency and percentage of semantic errors. Significant negative correlations (r=−.573, −.675) were found between proficiency and the percentage of acoustic errors.