My mother ruined my favorite Agatha Christi stories for me in much the same way. I always pronounced my wonderful detective Hercule Poirot phonetically, thus "her-cu-lee(z) poi-rot". When sharing with my mother one of the stories she burst out laughing and said his name was pronounced "her-cule pua-row" like the French. To this day I stumble when I get to his name. No harm meant on her part but boy what a blow.
Egad