Court room clerks, assuming you mean stenographers, are trained in typing shorthand. Basically, this lets them type at upwards of 250 words/minute. Something far beyond untrained individuals.

For comparison, you are probably only able to type upwards of 80 to 90 words/minute using standard keyboards. And that is, again, with training.

There was a fun article recently that went over writing shorthand. Journalists used to be commonly trained in writing methods where they could get over 100 words/minute. I know of literally zero folks that are trained in that.