I thought you could only absorb the souls once per wall? Right now im getting one everytime o_O IM guessing this was released through dawnguard.

Per wall? You don't absorb souls through walls, as far as I know...

Im talking about the dragons that respawn there O_O

If it spawn a different type of dragon you should be able to. Say you killed a fire dragon there last time and come back to find a frost dragon, etc. As far as I know if it is exactly the same type of dragon it does not give a soul, but I have not tested this since Dawnguard came out.

This existed before Dawnguard, I have been unable to get souls from respawned dragons @ word walls for a while now.

i dont think you get those souls again. it happens to me all the time

Each dragon respawn is its own entity. You'll continue to get souls no matter how many times you go back to the same place. If you don't get a soul, it's due to a bug unrelated to the location.

I've never gotten a 2nd soul from a word wall Dragon if I went back. Though I do get the bones and scales and other loot.