I know how to set up custom styles in Wyvern and Wygwam so that my client can apply, say, a <dfn> tag or <abbr> tag to some text. And I can set attributes within that tag. But the values of the attributes (in this case, lang and title attributes) are hard-coded via the custom style configuration.
Is there any way, using either Wygwam or Wyvern, to let the client specify the content of those attributes without them having to click the Source button and wallow around, shrieking, in the raw horror of HTML?