Language in action: the cross-domain role of language in the sensorimotor encoding of novel actions

Language and action are fundamental human cognitive abilities that share partially overlapping neural substrates and functional mechanisms. While action learning has traditionally been investigated taking into account predominantly visuomotor processes, growing evidence suggests that language plays a significant role in shaping perception, cognition, and motor behavior. This thesis expands this literature, investigating the contribution of language—explicit (verbal labels) and implicit (inner speech and inner labels)—to the acquisition and execution of novel actions. The thesis develops along two complementary but highly integrated lines. First, it examines whether associating novel verbal labels with novel action sequences facilitates learning, categorization, and execution. A preregistered behavioral experiment, including a kinematic protocol, showed that labeling induces faster reaction times and action execution times compared to a control condition, despite comparable encoding and accuracy levels, therefore suggesting a hierarchical structuring of motor sequences. Second, the thesis investigates the implicit contribution of inner speech to action learning. In a preregistered behavioral study, articulatory suppression was applied during action encoding to disrupt inner speech, while a control group performed a dual task matched for cognitive demand. Articulatory suppression significantly reduced action accuracy and execution quality and increased the proportion of non- learners, demonstrating a causal role of inner speech in motor encoding. Self-report measures confirmed the effectiveness of the manipulation and suggested that condensed forms of inner speech may partially persist under suppression, positively influencing motor performance. Finally, the thesis presents a neuroimaging project whose aim is to investigate whether inner speech neural patterns are recruited during action observation, encoding, and recall. Preliminary fMRI technical and behavioral pilot data are reported to inform the forthcoming fMRI study. Overall, the findings support a model in which language functions as a structuring and control system for motor learning, extending embodied cognition accounts and offering implications for clinical rehabilitation, sport training, and language-conditioned artificial systems.