13. The apparatus of claim 1 , wherein the acoustic model is trained by using one or more second training speeches respectively generated based on frame sets differently extracted from a same first training speech.
14. The apparatus of claim 13 , wherein, for the training of the acoustic model, the processor is configured to: extract the frame sets from the first training speech; generate the one or more second training speeches by respectively using the extracted frame sets; and train the acoustic model by using the generated one or more second training speeches.