Vow of silence
From Vanathul Wiki
Prerequisite(s): Silent Spell, Having taken the vow of silence at Brugenheim.
Benefit: You may eschew any verbal component when casting a divine spells as if it was cast using Silent Spell metamagic. This does not increase their level or casting time.
Special: If you voluntarily speak at any point after gaining this feat, you immediately loose any benefit it provides until you atone for your violation (see atonement)