I don't get with your comparing between: "ນາງ+surname" & "ແດງ+surname" ແດງ originally means: "red" "ນາງ" can use as calling "girl" . The most important thing that you have to consider before you call them is, they should be younger than you. If they are seem older than you:(Base on their ages & suppose that you are 20 years old) less than 20 years old: ນາງ 20-30 : ນາງ, ສາວ, ເອື້ອຍ 30-50: ນ້າສາວ 50 up: ແມ່, ປ້າ hope that it could help you