Q. Should sounds made by animals or objects be italicized when they aren’t part of dialogue (e.g., “quack,” “choo choo,” etc.)?
A. Though not required, such italics might have their place. Italics are common in fiction for unspoken discourse (as for a narrator’s thoughts). Such italics signal to readers that the words come from somewhere other than the narrative or dialogue. Consider also the convention used by many video captioners of italicizing words spoken off-screen. Meow. (Sorry, our editorial assistant must be hungry again.) If you do end up deciding that italics would work for you, try not to overuse them.