Firstly, I'd like to say I hope this is just a temporary solution to the eventual chat bubbles I wish ZOS would add to the game (over characters' heads). Until then, this an addon I've developed that should give you a similar experience.

The API can only allow static bubbles. Static bubbles do have some advantages, such as being able to see messages when the character is not in line-of-sight or field-of-view, and SCB supports additional channels beyond /say, /yell that most games restrict chat bubbles to.

If you have any questions/suggestions feel free to ask.

http://esoui.com/downloads/info136-SimpleChatBubbles.html