A method, performed by a device, of providing a response message to a user input includes obtaining location information of the device; executing a service providing agent corresponding to the location information; receiving a speech input from a user; generating the response message based on the received speech input, the response message being related to a service provided by the executed service providing agent; and displaying the generated response message, wherein the executed service providing agent generates the response message using a model trained using an artificial intelligence (AI) algorithm, the trained model being one from among a plurality of trained models each corresponding to a respective service from among a plurality of services provided by a respective service providing agent from among a plurality of service providing agents, and wherein the trained model corresponds to the executed service providing agent.