Luna recited the verses and the groom and the brides sat there quietly and listened to them. The language in which Luna was reciting the verses was the ancient vampire language.
Nobody talked in that language anymore or used it on a daily basis. Only during occasions such as marriages and stuff was the language used.
Saying anything in the ancient language was not something good. It had a lot of power in it and the consequences were severe if one recited it wrongly or said something wrong.
Every year, some or other vampire or being would think that it was just a joke and something the vampires were boasting. To test it out, they would try to recite some things and having no knowledge about it, they were bound to mispronounce things and this would result in either their vocal cords bursting, their head bursting, or their body or simply them dying silently.