Yes you are correct there is a bug of some sort with the game being able to read the “/The Elder Scrolls V Skyrim/Data/Skyrim – VoicesExtra.bsa” file when it comes to that Esbern character which means it screws a bunch of other stuff up if he’s involved apparently because it can’t find his audio files so it sort of hangs.
To remedy the bug you need to extract that “Skyrim – VoicesExtra.bsa” file using a BSA Extractor and then place the Esbern sound folder in your “/The Elder Scrolls V Skyrim/Data/” folder. By doing that you’re basically manually recreating the directory path the game is going to look for the audio files in. ie. “/The Elder Scrolls V Skyrim/Data/sound/voice/skyrim.esm/maleuniqueesbern”
Unfortunately though most BSA extractors seem to require Oblivion to be installed or some even plain just don’t work on Skyrim bsa’s for some reason so if you want just the Esbern sound files without trying to find a working BSA extractor you can grab them here (I just uploaded them for you) so that way you don’t need to bother with any extractors etc.
DOWNLOAD (sound.rar) – http://www.multiupload.com/P4HR8FKUFS
Bethesda will likely have this bug fixed in the next patch though, although if you can’t wait and want to play through then just put the extracted “sound” directory into your Skyrim “/Data” directory and you’re good to carry on with all the stuff that involves that Esbern character.