zlacker

It can depend a lot on different factors like:

- familiarity with the accent and/or speaker;

- speed and style/cadence of the speech;

- any other audio that is happening that can muffle or distort the audio;

- etc.

It can also take multiple passes to get a decent transcription.

>>rhdunn+(OP)
You missed a giant factor: domain knowledge. Transcribing something outside of your knowledge realm is very hard. I posted above about transcribing the commentary of a motorbike race where the commentators only used the slang names of the riders.