An electronic apparatus and a controlling method thereof are provided. The electronic apparatus includes a microphone; a memory configured to store a text-to-speech (TTS) model and a plurality of evaluation texts; and a processor configured to: obtain a first reference vector of a user speech spoken by a user based the user speech being received through the microphone, generate a plurality of candidate reference vectors based on the first reference vector, obtain a plurality of synthesized sounds by inputting the plurality of candidate reference vectors and the plurality of evaluation texts to the TTS model, identify at least one synthesized sound of the plurality of synthesized sounds based on a similarity between characteristics of the plurality of synthesized sounds and the user speech, and store a second reference vector of the at least one synthesized sound in the memory as a reference vector corresponding to the user for the TTS model.