The caster wards an area against a general topic of conversation. Those attempting to speak on such matters often find their interlocutors cannot hear them well, are oft interrupted, or have their meaning misconstrued. Attempts to persevere past this result in a -3 on any relevant checks.
In addition to this the caster may nominate up to one word per Air gnosis that cannot be spoken at all within the area. Prohibition of specific magic words may render the activation of enchanted devices impossible, however spellcasting in general tends to be more flexible. If the caster wishes to interfere with the words of a particular spells then the resulting difficulty increases their cost by one soul point. A mental saving throw may be used to contest this effect, but failure result in being rendered totally mute within the area.
Preventing your rival from speaking their own name to introduce themselves is considered quite funny among many adherents of Heron. However, despite much insistence, no sorcerer has yet survived a trial brought against them by preventing the judge from speaking the word “guilty.”