PHOENIX — The invitations to the border mayors’ meeting landed in inboxes in the United States and Mexico in English and in Spanish, standard for any type of official communication about binational events.

One of the guests, Mayor Ken Taylor of Huachuca City, Ariz., was incensed.

“I will NOT attend a function that is sent to me in Spanish/Mexican,” Mr. Taylor replied in an email to the invitation sent by John F. Cook, his former counterpart in El Paso and the executive director of the U.S.-Mexico Border Mayors Association.

“One nation means one language,” Mr. Taylor continued, “and I am insulted by the division caused by language.”

In an interview on Saturday, Mr. Cook said that he was flabbergasted by the reply, but that “I didn’t want to pick a fight.” So, in a response to Mr. Taylor, he wrote, “The purpose of the Border Mayors Association is to speak with one voice in Washington, D.C., and Mexico City about issues that impact our communities, not to speak in one language. My humble apologies if I ruffled your feathers.”