Board Thread:Lore Discussion/@comment-98.238.143.248-20130823010833/@comment-14743301-20150105075022

Nahfahlaar and Nafaalilargus seem to be indeed the same dragon

Nahfahlaar could be as well 'Nah-Fah-Laar' -> 'Fury-For-Clarity' or 'Clear/Apparent-Fury'

But if the Dragon got his name after his deeds under the service of Talos and as it is said that survived by making alliances with mortals then it is more likely to be 'Nah-Faal-Aar' -> 'Fury-The-Servant' as stated above with only some minor spelling changes as how the Blades recorded him, according to other sources in an obscure TES game the dragon considered itself as "Tiber Septim's proud Soldier, loyal Vassal, a jewel of the crown" so the Aar/servant part is more consistent with this information, the problem is that in that same game the dragon says his name is Nafaalilargus.

Now with Nafaalilargus although it is inconsistent with most known dragon names it could be something like:

'Nah-Fahliil-Aar-Gus' -> 'Fury-Elf / Mer-Servant-Unknown meaning'

And it could make us speculate with a little imagination that the dragon started working for the elves in exchange of protection and got the habit hence the name then worked for men and by the time of Tiber Septim his name might have changed a little as he was a fury in service of not only the elves.

So Nah-Fahliil-Aar -> Nah-Fahliil-Aar-Gus -> Nah-Fah-Laar / Nah-Faal-Aar