Word learning by naïve non-native speakers may not be predictable by cognitive test scores

The role of cognitive abilities in learning of words with two types of novel sounds—lexical tones and coronal consonants—was compared. Individual differences were expected to play a larger role in implicit learning of tones than consonants. Twenty-two English speakers took tests assessing working memory, attention, executive function, and processing speed (NIH & Northwestern University, 2006–2012, NIH Toolbox: Cognition). Then, they learned twelve Vietnamese words varying in their initial consonants [m, t, ʈ, ʐ] and tones (high level, falling, and rising). After training with feedback, the learning was assessed in a 12-word alternative identification test (N = 792). The range of accuracy scores was 11.1–80.6%, with the mean accuracy of 43.6% (SD = 18.5). The proportion of tonal errors was significantly larger than the proportion of consonantal errors [χ(1) = 174.68, p < 0.001]. Mixed-effect regression analyses showed, however, that cognitive test scores did not explain the variance in the word identificat...