BookBarbarian
Expert Long Rester
I'm new and coming into this late but I can't find a definitive answer to the OP. Some say yes. Some say no. Some say possibly.
The reason I was googling this question (halfling dragonborn) is because one of my favorite mythos has dragons (changelings so they have a human form) mating with humans. The catch (and what prevents mass extinction of one race or the other) is that only certain humans have a compatible dna. Details aren't gotten into but for a few humans it IS possible to bare dragon babies, or rather halflings.
Since there is no definitive answer would this line of thought be acceptable?
You could apply the Half-Dragon template from the Monster Manual to a Halfling, but this would be in my opinion more powerful than the Dragonborn race for a PC. But maybe not by so much as to be a problem.
Also, thank you for identifying that you were resurrecting an old thread. Hopefully that will keep people from responding to Posts that are a couple of years old.