Methods, systems, devices, and computer-readable storage media for activity detection of a user of a computing device, using multi-modal sensing. A device can be configured to receive sensor data corresponding to multiple modalities and process the sensor data to predict an activity performed by a user of a computing device. The device in response to the detected activity can perform a response action, such as muting or pausing audio playback from the computing device. Different modalities can be combined, such as body vibration data, air vibration data, and image data, which can be processed to distinguish user activity, e.g., speaking versus not speaking, to allow the computing device to perform the correct corresponding action.