What is the test for standing in an action brought by the US Department of Justice seeking to prevent the use of English as an official language?

The district court granted the government's motion to dismiss the action with prejudice, holding that Plaintiffs failed to establish standing on prudential grounds because they alleged only generalized grievances. Specifically, the court concluded that Plaintiffs assert only generalized claims on behalf of an extremely broad class of persons or entities that pay for interstate shipping or are consumers of goods that have been shipped in interstate commerce.... This type of broad, generalized allegation is simply insufficient to meet standing requirements. The court's order cited Arizonans for Official English v. Arizona, 520 U.S. 43, 64, 117 S.Ct. 1055, 137 L.Ed.2d 170 (1997), and United States v. Hays, 515 U.S. 737, 743, 115 S.Ct. 2431, 132 L.Ed.2d 635 (1995), among other authorities.

Plaintiffs appealed.