Seventh grader Sulayman Abdirahman of Mattapan’s Brooke Charter School is Boston’s newest spelling bee champion. He out-spelled 18 elementary and middle school competitors from across the city on March 19. The final word-off lasted a marathon 26 rounds between Abdirahman, a Roxbury resident, and sixth grader Anneliese Yu from Eliot Elementary. In the end, Abdirahman won with