A system comprising: a microphone; a speaker; at least one processor operatively connected to the microphone and the speaker; and a memory operatively connected to the at least one processor, wherein the memory is configured to store a natural language understanding, NLU, module, a first response model, and a second response model and to store instructions, when executed, that cause the at least one processor to: in a first operation, receive a first voice input including a first wake-up keyword for calling a voice-based intelligent assistant service, via the microphone, select the first response model based on the first voice input, receive a second voice input via the microphone after the first voice input, process the second voice input, using the NLU module, and generate a first response based on the processed second voice input, the first response being generated using the first response model, and in a second operation, receive a third voice input including a second wake-up keyword different from the first wake-up keyword, via the microphone, select the second response model based on the third voice input, receive a fourth voice input via the microphone after the third voice input, process the fourth voice input, using the NLU module, and generate a second response based on the processed fourth voice input, the second response being generated using the second response model. a microphone; a speaker; at least one processor operatively connected to the microphone and the speaker; and a memory operatively connected to the at least one processor, wherein the memory is configured to store a natural language understanding, NLU, module, a first response model, and a second response model and to store instructions, when executed, that cause the at least one processor to: in a first operation, receive a first voice input including a first wake-up keyword for calling a voice-based intelligent assistant service, via the microphone, select the first response model based on the first voice input, receive a second voice input via the microphone after the first voice input, process the second voice input, using the NLU module, and generate a first response based on the processed second voice input, the first response being generated using the first response model, and in a second operation, receive a third voice input including a second wake-up keyword different from the first wake-up keyword, via the microphone, select the second response model based on the third voice input, receive a fourth voice input via the microphone after the third voice input, process the fourth voice input, using the NLU module, and generate a second response based on the processed fourth voice input, the second response being generated using the second response model. in a first operation, receive a first voice input including a first wake-up keyword for calling a voice-based intelligent assistant service, via the microphone, select the first response model based on the first voice input, receive a second voice input via the microphone after the first voice input, process the second voice input, using the NLU module, and generate a first response based on the processed second voice input, the first response being generated using the first response model, and receive a first voice input including a first wake-up keyword for calling a voice-based intelligent assistant service, via the microphone, select the first response model based on the first voice input, receive a second voice input via the microphone after the first voice input, process the second voice input, using the NLU module, and generate a first response based on the processed second voice input, the first response being generated using the first response model, and in a second operation, receive a third voice input including a second wake-up keyword different from the first wake-up keyword, via the microphone, select the second response model based on the third voice input, receive a fourth voice input via the microphone after the third voice input, process the fourth voice input, using the NLU module, and generate a second response based on the processed fourth voice input, the second response being generated using the second response model. receive a third voice input including a second wake-up keyword different from the first wake-up keyword, via the microphone, select the second response model based on the third voice input, receive a fourth voice input via the microphone after the third voice input, process the fourth voice input, using the NLU module, and generate a second response based on the processed fourth voice input, the second response being generated using the second response model.