Final answer:
The speed of service for 'Immediate' messages is meant for urgent communications that should be dealt with within 30 minutes, though the question seems to conflate military communication with the creation of campaign slogans.
Step-by-step explanation:
The speed of service for Immediate messages within military or certain procedural communications indicates that the message has a priority status and should be delivered within 30 minutes. Prosigns, which are procedural signals in Morse code or other communication protocols, would be used to categorize these messages and ensure prompt delivery and handling. Given that the provided information talks about sound bites and campaign slogans, it appears there might be some confusion with political campaigning or media relations terminology. However, the question seems to relate specifically to communication procedures where time-sensitive information must be conveyed rapidly.