Manuscript Preparation, Copyediting, and Proofreading
Q. I’m editing a novel in which a character stutters on the first word of a sentence. Are both instances capitalized (e.g., “M-My name is” or “M-my name is”)? And do I use a hyphen or an em dash?
A. CMOS is silent on how to write a stutter, but Chicago style tends to favor lowercasing when there’s a choice. Neither style is likely to cause a problem for readers. A hyphen is normally used between letters; an em dash would work if whole words are repeated.