UPDATE: One party tells WWL's Don Ames they are in settlement talks; other litigants still prepared to go to trial.

A New Orleans court will decide today whether 'Who Dats' can wear their hearts on their sleeves, their backs, their caps and their koozies without contributing to the coffers of Sal and Steve Monistere.

The brothers claim they trademarked the phrase in 1983 and businesses selling 'Who Dat' items should pay royalties for the use of the phrase.

Steve Monistere says he trademarked the phrase 'Who Dat' in 1983 for his business and is suing to maintain the rights for its use on apparel, food and drinks.

But, attorney Doug Sunseri says that trademark expired in 1993.

"Then, when the phrase became really popular and profitable, in connection with the Saints' Super Bowl appearance, they reasserted their rights under that trademark saying 'That's ours. Anybody who uses it in the context of food, drink or apparel...they have to pay us for royalties," says Sunseri.

The Monistere brothers say the original trademark and its subsequent use in merchandise they sold long before the Saints' Super Bowl win in January 2010 gives them exclusive rights.

Steve Monistere says they're seeking those rights specifically on the use of the phrase for food, drink and apparel because they were the first to sell those types of products using 'Who Dat.'

Keith Moody, the owner of Monogram Express in Metairie, and the owners Who Dat Y'at Chat Cafe in Chalmette are suing over their claim.

"If the court rules that it is a trademark of the Monistere brothers, then those vendors would have to pay royalties to them, Sunseri says. "Now, the vendors are going to say that the trademark expired in 1993...it wasn't in existence at the time of the Super Bowl. Plus, you can't trademark something as generic as 'Who Dat' since it's been in the public domain since the 1870s."

Sunseri says that's when the term 'Who Dat' started out in minstrel carnivals.

"Then, they had several high schools in the New Orleans and Baton Rouge area in the late 70's who used the term 'Who Dat.' And, it was actually used by LSU in 1980 in connection with their Final Four run for basketball ('Who dat gonna beat dem Tigers')."

"And then, it sort of migrated over to the Saints in 1983. So I think they have a very strong argument to say that this is something that has been in the public domain...this is something for everyone to use and you cannot trademark that particular name. And, you didn't take enough steps to make sure your trademark encompassed that phrase in the context of food, drink or apparel. It's part of the public domain."

The battle over the phrase has been going for three years.

The New Orleans Saints and the NFL lost their claim to 'Who Dat' in 2010, when Louisiana Attorney General Buddy Caldwell decided the phrase was in the public domain and no one owned exclusive rights.

Sunseri says that decision may say a lot about what will happen in New Orleans today.

"The NFL did not prevail on that. And the NFL's got some powerhouse lawyers and a powerhouse organization behind them. So, if the NFL can't win that, I don't see the Monistere brothers winning it."