Silent coach: The role of inner speech in learning and performing new chunked actions.

Many people use inner speech (IS), the internal language, for self-guidance, planning, and simulating conversations. Research suggests it serves as a cognitive tool, primarily in executive functions, but its role may extend to other cognitive domains. This study investigates whether IS contributes to action learning and, therefore, execution. We examined whether observing novel, sequential, and non-meaningful actions would engage IS to support their encoding. To test this, participants observed actions to be learned while continuously repeating a syllable (articulatory suppression, AS) during the encoding phase, to prevent them from using IS and maintain verbal information. A control group performed a finger-tapping task at the same frequency as the AS to control for the cognitive demand of a dual task. Participants in the AS condition demonstrated lower accuracy and poorer execution quality in subsequent action recall and reproduction--execution phase--with a significantly higher number of non-learners-individuals unable to reproduce the actions. Furthermore, participants' self-reported IS use was significantly lower during the encoding (AS present) than during the execution phase (AS absent), confirming the disruptive effect of AS. These findings suggest that IS plays a crucial role in action learning by facilitating the encoding and retrieval of novel movements. Beyond its well-established role in executive functions, IS appears to contribute to broader cognitive processes, including motor learning. By highlighting its impact on action acquisition, this study expands our understanding of IS as a versatile cognitive tool, providing new insights into its function in learning and execution across domains.