The manager of a Dunkin' Donuts shop who told his employees to speak only English in front of the customers is an Ecuador-born 20-year-old who said he was just responding to customer complaints. But the sign he posted, inviting customers to complain if they heard foreign conversation behind the counter, got the attention of the corporate office. Dunkin' Donuts said the manager's approach was inappropriate. The chain does require employees who interact with the public to be fluent in English, but it doesn't forbid them from speaking other languages. A company statement says the ability to speak other languages helps...