I heard in another post that they are used for shouts, but how?

In the shout menu, go to an locked shout and you will see the button you must press to use a dragon soul to unlock shout. In PC it's "R".


Right there on the screen.

Wow! Thank you! Kept killing these dragons and absorbing the souls, and couldnt figure out for the life of me what the point of absorbing the souls was for.

Yeah, when I first started playing, I missed how to you had to manually spend souls to unlock shouts. There are tooltips for other things like alchemy, forges, enchanting, but nothing for when you want to use/unlock shouts.

And to make everything clear, you also need to learn the words to the shout, simply having souls isnt enough. Theres word walls all over skyrim, many in locations associated with various quests.