Trim fat from pork; cut pork into 1-inch cubes. Peel, core, and chop two of the apples; set aside. In a large pot brown pork, half at a time, in hot oil. Return all pork to pot; add chopped apples, onions, curry powder, coriander, and cumin. Cook and stir for 2 minutes. Add broth, salt, and pepper. Bring to boiling; reduce heat. Simmer, covered, for 30 minutes, stirring occasionally.
Add carrots to pork mixture. Return to boiling; reduce heat. Simmer, covered, for 20 minutes, stirring occasionally. Meanwhile, cut the remaining two apples into 1/4-inch-thick wedges; add to pot along with squash. Cover and cook 10 to 12 minutes more or until pork and vegetables are tender.