It would transcribe what you recorded ahead of time. You can use a voice recorder to record audio and process the audio through the software.
It is useful for transcribing speech into text, either as an installed software on your computer or as a transcriber. Instead of typing texts, you say what you want to write, and Dragon will take care of it for you. Dragon Naturally Speaking is a speech-recognition software that turns the sound signals of your voice into text output.