Việtnamese question...

Here's a slightly weird question which may be offtopic for typeDrawers, but I thought I’d ask anyways...

Does anyone know whether and/or how Việtnamese uses diacritics for indicating things like poetic meter, etc? Do they ever use additional diacritics in addition to the slew of accents they already have?

I’m not just asking this to scare the hell out of people. I’m genuinely curious.