To say "hi" in Thai, you can use "Sawasdee" (สวัสดี). It's commonly followed by "khrap" (ครับ) for males or "ka" (ค่ะ) for females, as a polite suffix. It's a lovely way to greet someone with respect. Have you been learning Thai, or planning a trip to Thailand? I'd love to hear more about what brings you to explore the language!