Whether your native tongue is British English or American English, the dress code for the wedding of Darrell Silver and Stephen Foley is: "cocktail attire".
The rehearsal dinner on Friday has no dress code.
Both American and British men are required to wear pants. Pants are also compulsory for British women, but optional for American women. If men are intending to wear a vest, it is requested that American men do so over their shirt, while British men are required to keep their vests under their shirts.
Jumpers and sweaters are both frowned upon. Similarly, bum-bags and fanny packs. Sneakers will not be allowed under any circumstances, and trainers will be admitted only with an invitation.
Women are permitted to wear flats, but not apartments, since that makes no sense. Zips and zippers must both be done up.
Braces are optional for English men, and American men should wear them only on the advice of a dentist. As for suspenders, each to his own.