I wondered about that too. "Kobold" I can understand. Drow should have the sign for them. But accountant? Given as the most plausable purpose of the language seems to be the silent communication before the battle, how many times before in Drow history the word "accountant" came up in pre-combat chat?
Spoken like someone who has never been on a Drow corporate retreat. Let's just say they do more than drop you on purpose during the trust fall.