This is a sound that English speakers make in a few different situations:
- When something disappointing happens:
Aw, my strap broke!
- When you see something cute:
- When someone does something sweetfor you:
Aw, thank you! You shouldn't have! (When someone gives you a gift.)
The example above is probably closest to #3. When people pay you a compliment, you can start your response by saying "Aw":