[Coda]

Because it is.

Every discipline has its jargon -- this isn't unique to software engineering. Doctors can talk about things and understand each other but someone listening in without their experience and knowledge of their jargon wouldn't be able to comprehend the discussion.

Since the point of language is to facilitate communication between people, you can consider someone to be speaking a different language if you can't understand them but someone else can. (If NOBODY can understand them, they may just be crazy. ;) )