EVERETT — Pope John XXIII High School once epitomized the parochial school experience, a concrete building where hundreds of poor Catholic children from Irish and Italian immigrant families sought a new future. For decades, a student from farther away than Malden or Chelsea stood out. ​

Walk through the same doors now, and the tones of Mandarin Chinese bounce off the lockers. International flags fly between stained glass windows in a chapel-turned-dining hall. In one classroom, a crucifix hangs over a bookshelf with a Chinese dictionary — a reminder that almost half the school’s population hails from abroad. Three-quarters of those students come from China.