Research in cognitive neuroscience has shown that brain structures serving perceptual, emotional, and motor processes are also recruited during the understanding of language when it refers to emotion, perception, and action. However, the exact linguistic and extra-linguistic conditions under which such language-induced activity in modality specific cortex is triggered are not yet well understood. The purpose of this study is to introduce a simple experimental technique that allows for the online measure of language-induced activity in motor structures of the brain. This technique consists in the use of a grip force sensor that captures subtle grip force variations while subjects listen to words and sentences. Since grip force reflects activity in motor brain structures, the continuous monitoring of force fluctuations provides a fine-grained estimation of motor activity across time. In other terms, this method allows for both the localization of the source of language-induced activity to motor brain structures and the high temporal resolution of the recorded data. To facilitate comparison of data to be collected with this tool, we present two experiments that describe in detail the technical set up, the nature of the recorded data, and analyses (including justification about data filtering and artifact rejection) that we applied. We also discuss how the tool could be used in other domains of behavioral research.