Amazon Transcribe is a cloud based automatic speech recognition service that can currently (2017) convert from speech to text documents in 2 languages - English and Spanish. The transcribe service can convert speech to text from audio files stored in S3 and can return the text file containing the speech.
Amazon Transcribe can be used to process customer service calls, to record meeting notes and to generate subtitles for audio and video. Audio files in WAV and MP3 formats can be transcribed with time stamps on where the audio appears in the file.
Note that the data processed by Amazon Transcribe can be used for quality purpose by AWS and could be accessible to authorised employees on Amazon. Read FAQs for further details.