School bells will ring extra early at Southern Maine Community College next semester. The South Portland school will offer 10 early-morning classes in the spring 2013 semester, with start times of 7 a.m. and 7:30 a.m. The college says the added flexibility in the schedule is designed to serve two purposes. It will provide more options for the college’s increasingly diverse student population, many of whom are working professionals or have family demands. The change will also help to ease traffic congestion on Broadway, the main South Portland artery to SMCC, during the morning commute.