In military communication, the most standard way to express "OK" or "understood" is to say "Roger" or "Roger that." This term originated from the phonetic alphabet (where 'R' stood for 'Received') and signifies that a message has been successfully heard and processed. However, "Roger" specifically means "I have received your message," whereas if you intend to say "I understand and I will carry out the order," the correct term is "Wilco" (short for "will comply"). You should never say "Roger Wilco" together, as it is redundant. Another popular term, especially in the U.S. Army, is "Hooah," which is a versatile expression used to say "OK," "Understood," "I agree," or to show high morale; the Air Force equivalent is "Hua," and the Marines use "Ooh-rah." In 2026, while "Roger" remains the gold standard for radio etiquette to ensure absolute clarity and brevity, these other cultural markers continue to define the linguistic landscape of the various service branches.