I don't know if it's specifically what Okrand had in mind, but my mind instantly goes to "Das Boot" as potential inspiration for this word. Groan ... the eternal bad German/English pun. :-D
He has confirmed that that is exactly what he had in mind.
Das Boot is said to have been one of the inspirations for having the Klingons speak subtitled Klingon on their ships in the Star Trek films. We may owe the very existence of tlhIngan Hol to Das Boot.
I guess I should actually watch Das Boot one of these years, then. :) Thanks.