아/야: Calling someone's name

How it sounds, and the extra 이

With a name that ends in a consonant, the consonant slides into 아. So 지민아 jimina sounds like "ji-mi-na", and 은정아 eunjeonga like "eun-jeong-a".

Those same names also pick up an extra 이 i in casual talk, before other particles:

• 지민이가 왔어. jiminiga wasseo "Jimin's here."
• 은정이는 어디 갔어? eunjeongineun eodi gasseo "Where did Eunjeong go?"

This 이 is just friendly. It doesn't change the meaning, and names ending in a vowel don't get it: 민수가 minsuga, never 민수이가 minsuiga.

What to use with everyone else

아/야 is for people you're close to and who are your age or younger. For anyone else, there are safer choices:

• Someone your age you're not close to: the name plus 씨 ssi, like 민수 씨 minsu ssi.
• Someone older you know well: a family-style title, like 언니 eonni, 오빠 oppa, 누나 nuna or 형 hyeong.
• A teacher or boss: the title alone, like 선생님 seonsaengnim or 팀장님 timjangnim.

야 on its own

야 ya by itself means "Hey!" Between close friends it's normal. To a stranger, it sounds rude and a bit aggressive, so it's best kept for people you know well.