Though it's hard to tell in D&D whether the races are actually different species. I mean obviously men can breed successfully with elves and orcs, because we have half-elves and half-orcs. But I've never heard of a half-dwarf.
Would the offspring of a human and a halfling be a half-halfling? Or a three-quarterling?
It would be either a human or a halfling depending on the what the mother is. It would have physical characteristics from both parents but would be either squarely a human or a halfling.
