When typing in a forum such as this, my personal rule is to use standard quotation marks "...." for known exact quotes, but when there is a phrase I am not sure of, or that *I* claim as my own creation, I like to use single quote apostrophes '....'.

It's just my attempt to indicate in print what I would try to show in speech. Mudcat is great in allowing various HTML code to allow ^rising and _falling inflection etc....