Originally Posted by Narse
Do spells with a verbal component need to be spoken loudly, or can they be spoken softly?
From the PHB:
Verbal (V): A verbal component is a spoken incantation. To pro-
vide a verbal component, you must be able to speak in a strong voice.
The flavor text of Cheat may imply a contradiction to the RAW, but for the purposes of this thread it isn't binding. If you want to whisper or mumble a spell, your DM will need to approve.