If you want to better understand the origins of a Martial Art, the answer lies in Lanuage, and if you trace back a countries lanugage, then you will have a better idea of the origins of a specific Art.
I believe that all Martial Arts are directly related to the time line of Mans Evoluton, and Transmigration from one place to another. If you go back 40 years, there would be taekwondo, go back 90 years and there isnt, only Japanese based styles, go back 150 years and only Taekyon styles, but like any Nation, or Dynasty, you had to have a army and the skills of the troops were taught to them be someone else. What I'm trying to say is that Taekwondo like everything else in life gets passed down from person to person, sometimes that information gets lost due to peoples becoming isolated, or people getting completely wiped out (genocide) by another Tribe or army. If you go back far enough in time, you could say that the origins of Taekwondo are in fact African, if you believe that modern man are all descendants from there and simply migrated outwards. If a caveman teaches his son to hit things or other caveman with a dinosaur bone, couldnt that be classifiead as a form of Martial Arts. That skill is being passed down, from Master to Student. Martial Arts. like most things in life has to be learned from someone else, and if someone teaches that martial art to others, then te next generatin of Masters will change it to some degree. We can even see this in the way Present Day Masters Teach. Most Masters slightly change they're style of a Martial Arts depending on outside influences, or simply their own beliefs might change. When a young Master teaches, he may focus on speed, but as he ages he might decide that power is more important. Therefore that same Master has change his own Art slightly.
Master John Huh