You notice a distinct smell of sulphur, the temperature in the room rises by a good 5 degrees. A circular cloud of black smoke puffs into existence. As it clears, it reveals a round, 2ft diameter window into what can only be Hell. A familiar yet condescending* voice speaks quickly, in a mind-numbing, near constant drone of syllables:
Dessiter (you may recall his rather unique appearance from when you first signed your contract with the Cardinal) extends one of his arms and another document unfolds from a sleeve. Just, but only just, in time to catch Letho's drop in an obnoxiously lazy manner on an entirely different document.
In an instant, Dessiter withdraws his document and arm, while the window is already closing.
There isn't much time to recover from your surprise, as Letho's name on your copy of the contract bursts in flame, and runes crawl over it to seal it in place.
* condescending would be an understatement. Then again, most of the time spent learning Infernal goes into understanding the vocative cases, in other words, the endless forms of referring to others.
Protocol is everything, but practically every other word is condescending. Think of devils as the worst bunch of lawyers, being allowed to construct a bureaucracy for themselves, which has only one purpose namely to ensure that the lawyers who made the laws can remain in place. There's no logic, there's no understanding, there's just cold hard knowledge, and lots of opportunities to fail.
For example, there's no such thing as "he" in Infernal; there are at least a thousand forms of "other-who-is-superior", and probably several thousands that suggest "other-who-is-lesser". And then there's all the variations of "other who is not present but superior" et cetera, ad infinitum.
Calling a barbed devil "Most Vile Specialist" instead of "Utmost Vile Specialist" would be a seen as a grievous insult, punishable by being fed to Lemure Devils.