아

calling someone by name

Tacked onto a name or noun ending in a consonant, it's the casual way to call out to someone: 유진아! 'Yujin!', 아들아 'son!', 얘들아 'hey, you guys'. After a vowel the same call becomes 야 (민수야). It is for people you're close to or above in age — using it with a stranger or an elder is rude. Note that the 아 opening many subtitle lines is just the sound 'ah', a completely different thing.

Register: casual; close relationships or downward only