This salutation or greeting is similar to "Aloha" in Hawaii. Just as Hawaiians are well known for saying "Aloha!" so are the natives of Guam just as well known for saying "Hafa Adai!" The greeting "Hafa Adai!" is literally translated into English as "What Friend" or "What Partner" But, because the literal translation loses meaning, the best or most close meaning is "How are you, Friend?" Or, "What's up Friend?" or "Hello!" A greeting you would say to someone you consider a friend. In Guam, the Chamorro greeting is a very friendly way of welcoming people. It's Polite, and Friendly. If you see a Guam Bumper sticker in the USA it will most likely say "HAFA ADAI" on it. The correct pronunciation of Hafa Adai is just like "Half a Day".
A Chamorro girl sees a cute Island Boy (Chamorro Boy) walking past her and she smiles kindly and says "Hafa Adai" and he nods and says "Hafa Adai" back.
As they pass each other they both smile. Two strangers greeting each other as friends. :) That's the Chamorro way.