Entirely possible. We don't know the function of the Masks; Were they crafted for the dragonpriests, or are they similar to the Eldar Phoenix Lords of Warhammer 40k? As in, the person who wears the mask becomes the mask? It's possible that it takes some time for the effect to take hold, and the original Dragon Priests were simply the last ones to wear the masks with no successors. In this instance, "Konahriik" had an original owner, but the body decayed too much (or was ripped off and the priest slain) and was left in the dust.
If the masks took control of someone, it would have been more beneficial for it to happen immedately or within a few weeks or months of being worn. What better leader than one who has the wisdom (and power) that hundreds of lifetimes can offer?
You are suddenly my friend.
One of the things that got me thinking that the masks were this way is Jack of Blades from fable 1, his mask is him, the body he uses is the body of a host that the mask corrupts, and thus he has control of the body itself, this change is instant also, as shown when the Hero puts the mask on, Jack takes over.
How do you know that Konahriik had an owner and his body was decayed? If it was left in the remainders of its owner why is now safeguarded in Bromjunaar Sanctuary?
Also, how i would love to able to wear the robed armour of the Dragonpriests :0 They need the make this DLC..
EDIT: Also, the word for the language is 'Dragonish', since latin is not a language in the world of TES, 'Draco' is not a word at all, making 'Draconic' redundant, the language i suppose would be better call 'Dovish' but substitute whatever 'ish' would be in their language..