A server is provided. The server includes a communication circuitry, and at least one processor operatively connected with the communication circuitry. The at least one processor may be configured to, in response to traffic of a plurality of speeches to wake up a voice assistant feature, received within a preset period being a preset value or more, generate a plurality of clusters based on similarities between the plurality of speeches, and determine whether to respond to each of speeches included in each of the plurality of clusters based on similarities between the speeches included in each of the plurality of clusters.