Web Speech Demo (Web Speech API)
A Google demo page showing how the browser's built-in speech recognition works. Speak and your words are transcribed into the box on the spot, and you can pick the recognition language from a long list that includes Korean.
How to try it
Click the microphone icon at the right of the text box, allow the browser's microphone permission prompt, and start speaking. Choose "한국어" from the list below to transcribe in Korean; the transcribed text can be copied or sent to your mail app. A microphone is required and the on-screen text is in English only.