Doublespeak

You cover your mouth and voice in a thin sheet of illusion, distorting your words. When you cast this spell, until the end of your next turn, whenever you speak, you choose both what you actually say and what others hear. These do not need to be similar phrases, and in fact, you may say nothing and have others hear a sentence, or say something and have others hear nothing. A creature can see through this illusion by making an investigation check versus your spell save DC, when they realize this speech as illusory, they both understand what you have said and what you wanted them to hear, additionally when a creature makes this investigation check and succeeds, they automatically succeed investigation checks against your subsequent castings for 1 hour.