I prefer people as an alternative to parent race. For subrace, I think it would be best to have terms that are specific to the particular people of which the subcategory is a part. For instance, a dwarven subcategory could be called a clan or a house, an elven subcategory could be called a division or a sundering, and a halfling subcategory could be called a descent, a blood, or a breed. This would echo how subclass has been treated (which as a term seems to be absent from the books) and has been replaced by terms specific to each class: path, college, domain, circle, archetype, tradition/way, oath, origin, patron, and tradition/school.