Mayor Thomas M. Menino and a coalition of advocates are set to mark the 10th anniversary of an English language program that has helped thousands of the city’s immigrants. The mayor is scheduled to honor the English for New Bostonians program at Northeastern University tomorrow. More than 10,000 immigrants in Boston have taken classes under the program, which started in 2001. Officials say they hope to expand the program, which has recently received new grants from the Smith Family and Barr foundations. The Boston Foundation released a study this month showing that only 5 percent of immigrants in the Boston area who need it are receiving English instruction.