Three punctuation marks commonly used in transcripts that may be confusing are the dash, ellipsis points, and brackets.
A dash is used when a speaker changes or clarifies an idea in midsentence or when the first speaker is interrupted by a second speaker and the first speaker resumes the original idea.
(a) We’ll call Miss — Mrs. Jones to testify.
(b) Elizabeth came to my house Tuesday or Wednesday — yesterday was Thursday — Wednesday.
(c) Q. Do you have the checks?
A. I have them in —
Q. Are they canceled?
A. — my safe deposit box.
A pair of dashes is used when a speaker suspends but does not cancel the idea in midsentence and then continues the idea.
(d) I always shop – this may sound strange – at my first husband’s store.
Reference: Morson, Lillian. (1997). “Morson’s English Guide for Court Reporters,” 2nd edition.