Until now, city students learning English as a second language had to take important standardized tests in reading and math in English, even if they have been in the United States less than a year. Schools Commissioner Joel Klein announced Tuesday that’s about to change. “I thought it was a mistake to require everyone to take the exam after the first year,” said Schools Chancellor Joel Klein. “The federal government has now changed that, and in New York, at least, we’ll be able to exempt students for the first two years.”