There are some things that just cannot be unsaid.

It's a lesson that Papa John's executives and shareholders are learning the hard way.

"Very inexcusable and irresponsible comments" by company founder and former CEO John Schnatter caused same-store sales in July to plunge by about 10.5 percent, current CEO Steve Ritchie told analysts Tuesday in explaining the company's worse-than-expected performance during the the second quarter and drastically lowered sales forecasts for the year.

That's not going to improve any time soon. The company, which reported earnings after the market closed, lowered its outlook for comparable stores, saying executives now expect sales at stores open for at least a year to fall between 7 percent and 10 percent this year. Papa John's previously estimated that they wouldn't fall by more than 3 percent.

Its shares plummeted by almost 12 percent in aftermarket trading Tuesday.