Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

Listen to Oswald's voice at the MPC. I use this one from David Von Peinhead because it's includes all of it. Most renderings omit his first statement about his arraignment before the judge in which he protested being denied a lawyer. 

But, what interests me at this time is his voice. Notice that he doesn't sound like a guy who was born and raised in New Orleans and also lived in Texas. I would describe it more as an East Coast accent. Start at 25 seconds. 

http://jfk-archives.blogspot.com/2015/01/oswald-midnight-press-conference.html 

Now listen to Robert Oswald. This is the only recording of his voice that I can still find. I've heard others in which his Texas/Louisiana accent sounds even stronger. But, you can still hear it, and it's very different from LHO's. Start at 1:42.

https://www.youtube.com/watch?v=Vq0tjSwdm9Y

Now, remember that theoretically, Robert Oswald and LHO grew up in the same household, and in the case of LHO, one of the voices that would have influenced the formation of his own speech was that of Robert Oswald. Yet, they sound nothing alike. You hear the Texas and Louisiana in Robert Oswald's voice, but LHO's voice, again, sounds East Coast. 

They were were not brothers. They did not grow up together. And what happened to RO's real brother Lee remains a mystery. He could still be alive.