Systems and processes for proactive assistance based on dialog communication between devices are provided. In one example process, while voice communication between an electronic device and a second electronic device is established, a stream of audio data associated with the second electronic device can be received. In response to detecting a user input, a text representation of speech contained in a portion of the stream of audio data can be generated. The process can determine whether the text representation contains information corresponding to one of a plurality of types of information. In response to determining that the text representation contains information corresponding to one of a plurality of types of information, one or more tasks based on the information can be performed.