Functional neural specialization during word learning from linguistic context

Learning new words is essential for vocabulary growth and effective communication. While early word learning often relies on explicit instruction, much of vocabulary acquisition in later childhood and adulthood occurs through inference from linguistic context. Despite this, the neural mechanisms supporting auditory contextual word learning remain underexplored. In this fMRI study, young adults inferred the meanings of novel words embedded in sentence triplets that either supported meaning retrieval (increasing cloze probability) or did not (low cloze probability). Meaning-supporting sentences elicited greater activation in left frontal regions (inferior frontal gyrus, superior frontal gyrus (SFG), frontal pole (FP)), middle temporal gyrus, bilateral lateral occipital cortex (LOC), and thalamus. Activation in left SFG, left FP, and right LOC predicted faster meaning retrieval, with right LOC activation also predicting greater accuracy. Higher phonological working memory and processing speed were associated with greater learning accuracy, while cognitive flexibility and processing speed predicted faster retrieval. These findings indicate that a distributed frontotemporal network supports word learning from naturalistic speech, highlighting shared neural mechanisms across learning modalities and informing models of language acquisition.