[Object] Technology is provided to enable a mobile terminal to function as a digital assistant even when the mobile terminal is in a state where it cannot communicate with a server apparatus. [Solution] When a user terminal 200 receives a query A from a user, user terminal 200 sends query A to a server 100. Server 100 interprets the meaning of query A using a grammar A. Server 100 obtains a response to query A based on the meaning of query A and sends the response to user terminal 200. Server 100 further sends grammar A to user terminal 200. That is, server 100 sends to user terminal 200 a grammar used to interpret the query received from user terminal 200.