An electronic musical instrument comprising: a plurality of operation elements respectively corresponding to mutually different pitch data; a memory that stores a trained acoustic model obtained by performing machine learning on training musical score data including training lyric data and training pitch data, and on training singing voice data of a singer corresponding to the training musical score data, the trained acoustic model being configured to receive lyric data and pitch data and output acoustic feature data of a singing voice of the singer in response to the received lyric data and pitch data; and at least one processor, wherein the at least one processor: in accordance with a user operation on an operation element in the plurality of operation elements, inputs prescribed lyric data and pitch data corresponding to the user operation of the operation element to the trained acoustic model so as to cause the trained acoustic model to output the acoustic feature data in response to the inputted prescribed lyric data and the inputted pitch data, and digitally synthesizes and outputs inferred singing voice data that infers a singing voice of the singer on the basis of the acoustic feature data output by the trained acoustic model in response to the inputted prescribed lyric data and the inputted pitch data, characterized in that the plurality of operation elements include a first operation element as the operation element that was operated by the user and a second operation element that meets a prescribed condition with respect to the first operation element, and wherein the at least one processor applies an acoustic effect to the inferred singing voice data when the second operation element is operated while the first operation element is being operated. a plurality of operation elements respectively corresponding to mutually different pitch data; a memory that stores a trained acoustic model obtained by performing machine learning on training musical score data including training lyric data and training pitch data, and on training singing voice data of a singer corresponding to the training musical score data, the trained acoustic model being configured to receive lyric data and pitch data and output acoustic feature data of a singing voice of the singer in response to the received lyric data and pitch data; and at least one processor, wherein the at least one processor: in accordance with a user operation on an operation element in the plurality of operation elements, inputs prescribed lyric data and pitch data corresponding to the user operation of the operation element to the trained acoustic model so as to cause the trained acoustic model to output the acoustic feature data in response to the inputted prescribed lyric data and the inputted pitch data, and digitally synthesizes and outputs inferred singing voice data that infers a singing voice of the singer on the basis of the acoustic feature data output by the trained acoustic model in response to the inputted prescribed lyric data and the inputted pitch data, in accordance with a user operation on an operation element in the plurality of operation elements, inputs prescribed lyric data and pitch data corresponding to the user operation of the operation element to the trained acoustic model so as to cause the trained acoustic model to output the acoustic feature data in response to the inputted prescribed lyric data and the inputted pitch data, and digitally synthesizes and outputs inferred singing voice data that infers a singing voice of the singer on the basis of the acoustic feature data output by the trained acoustic model in response to the inputted prescribed lyric data and the inputted pitch data, the plurality of operation elements include a first operation element as the operation element that was operated by the user and a second operation element that meets a prescribed condition with respect to the first operation element, and wherein the at least one processor applies an acoustic effect to the inferred singing voice data when the second operation element is operated while the first operation element is being operated.