Faux 'stage' archaic Japanese dialect, used to emulate an Edo-era aristocrat or courtesan way of speech. Commonly given to dignified-sounding characters who speak in an old-fashioned style.
For female characters, this often heavily involves the use of "warawa" and "-nanoja", to the point that this is sometimes called the "nanoja dialect" or "nanoja loli (speak)".
This stage dialect is usually translated into English as a faux-Shakespearean dialect.