Korean Politeness Levels!
Type 1. -ㅂ니다 [-m-ni-da] = the most polite and most formal ending
Type 2. -(아/어/여)요 [-(a/eo/yeo)-yo] = the polite, natural, and slightly formal ending
Type 3.: -아/어/여 = the casual, informal, and intimate ending
Types 1 and 2 fall under the 존댓말 [jon-daen-mal] category, and Type 3 goes into the 반말 [ban-mal] category.
Addressing people
When politely addressing someone using 존댓말, add the word 씨, as in 경은 씨 [gyeong-eun ssi], 현우 씨 [hyeo-nu ssi], 석진 씨 [seok-jjin ssi], 소연 씨 [so-yeon ssi], and 현정 씨 [hyeon-jeong ssi]. If in a business or school setting, add the title of the person’s job or status after his/her name, such as 경은 선생님 [gyeong-eun seon-saeng-nim], 현우 회장님 [hyeo-nu hoe-jang-nim], etc., to show more formality toward the addressee.
When speaking in 반말, however, you can just say the name of the person without 씨. In order to make the name sound more natural when addressing the other person, add 아 [a] or 야 [ya] to the end of the name. Names that end WITHOUT a consonant are followed by 야 [ya], and names that end WITH a consonant are followed by 아 [a].
Ex)경은 → 경은아! [gyeong-eu-na!] (Hey Kyeong-eun!)현우 → 현우야! [hyeo-nu-ya!] (Hey Hyunwoo!)
Speaking in Third Person
When using a person’s name while speaking or writing in the third person, 이 [i] is added after names that end with a consonant. Therefore, names such as 경은 and 석진 are followed by 이.
If 현우 wants to talk about Seokjin in a sentence, he says Seokjin’s name as “석진이” [seok-jji-ni].