The effect of morphological salience and novel phonology in the initial stage of second language learning

This study investigates whether adult learners can simultaneously acquire the sounds, words, and grammar of a novel language through cross-situational statistical learning (CSL). English-speaking participants were exposed to an artificial language with unfamiliar phonology and varying morphological salience. Results showed measurable acquisition of nouns and verbs, but limited learning of adjectives and case markers. Importantly, only participants in the high-salience condition showed sensitivity to morphosyntactic violations, suggesting that perceptual salience enhances awareness of grammatical structure. A word–picture matching task revealed that learners encoded phonolexical forms imprecisely: while clearly deviant items were rejected, minimally different lures were often accepted. Finally, individual differences in phonolexical precision were only weakly associated with phonetic discrimination ability. These findings demonstrate the power and limits of CSL in second language learning and highlight the importance of perceptual cues for acquiring complex L2 structure.