Effect is instant

"What iz going on?" said John as he awoke. His voice was soft and had a hint of a french accent.

"You accidentally fell asleep in the fitting room," said Yvette, "We just woke you up. How do you feel?"

"I feel, how you say, weird..." John said grabbing at his throat. "Zis is not my voice!"

The woman began to look around the room and spot a mirror. Before Yvette or Petra could stop her she stood in front of it.

"What iz happened to moi?" John asked both scared and slightly mesmerized by his reflection.

Petra stepped forward, "You are the Maid of Honor for your friends Dave and Jessica, don't you remember?"

John began to stagger and almost fell back if it weren't for Yvette. "Merci beaucoup." she said reflexively.

Petra eyed John, clearly he had absorbed the French background she had implanted into him, but he was not quite ready to take on his position. "You know what you need to do, my dear?"

John blinked as she noticed Petra again, "What?"