|The Oseberg viking ship, 820 AD|
The Q-codes date back to 1912 and were meant to be a short-hand for use in telegraphy. According to the list of Q-codes which Ralf D. Kloth (DL4TA) has on his web page, the meaning of QOD with a number added is: "Can you communicate with me in ... 0 Dutch, 1 English, 2 French, 3 German, 4 Greek, 5 Italian, 6 Japanese, 7 Norwegian, 8 Russian, 9 Spanish?" As a response to the question the meaning was "I can communicate with you in ..."
The reason for a separate code for Norwegian must be the historically large shipping fleet in Norway. This is still the case as graphically depicted in this overview of the Top 20 Ship Owning Countries, where we seem to rank as number seven - so QOD7 is appropriate!
But today all of them will QOD1.
Image from Wikipedia, user Karamell