I am a native English speaker from the United States, and am more than capable of transcribing said audio files. I am also willing to provide a small sample of my transcription ability, likely in the form of transcribing a small portion of one of the audio files (say, 5 minutes). I do not use any software to complete my transcription tasks, they are all done manually.
If you have any questions, I'm more than happy to provide an answer!
Thanks!
Joe