Subject honorific -시-
You already know -요 is listener politeness — how nicely you're speaking. Korean has a second, separate layer: subject honorific -시- marks respect for the person performing the verb. When you talk about your boss, your teacher, an elder, or a stranger older than you, you slip -(으)시- into the verb. The two layers stack: you can be -요-polite and add -시-, or -요-polite without -시- (talking about a friend), and so on.
Form: stem + -(으)시-
Insert -시- between the verb stem and the ending. After a consonant, use -으시- for ease of pronunciation. 가다 → 가- + -시- + -어요 → 가세요 (= 가시- + -어요, contracted). 읽다 → 읽으시- + -어요 → 읽으세요. 하다 → 하시- + -어요 → 하세요. The familiar -(으)세요 ('please do', lesson 12) is exactly -시- + polite ending — that's why it sounds respectful.
Polite present, past, and future
Polite present: -(으)세요 = -(으)시- + -어요. 선생님이 가세요. = 'The teacher is going.' Past: -(으)셨어요 = -(으)시- + -었어요. 할머니가 가셨어요. = 'Grandma went.' Future-intent: -(으)실 거예요 = -(으)시- + -(으)ㄹ 거예요. 사장님이 오실 거예요. = 'The boss will come.' All three layers (tense, -시-, -요) stack predictably.
Special honorific verbs — different roots
A few core verbs have completely different honorific roots — you can't just add -시-. Memorize these: 있다 (be / have) → 계시다 (be, for people; 'is present') / 있으시다 (have). 자다 (sleep) → 주무시다. 먹다 / 마시다 (eat/drink) → 잡수시다 or 드시다. 말하다 (speak) → 말씀하시다. 죽다 (die) → 돌아가시다. 선생님이 계세요? = 'Is the teacher in?' 할아버지가 주무세요. = 'Grandfather is sleeping.' 드세요! = 'Eat (please)!' (very common at the table).
When to use -시-
Use -시- when the subject of the sentence is socially higher than you OR a respected stranger: parents, grandparents, teachers, bosses, customers, elderly people, strangers in general. Don't use -시- about yourself — never 저는 가세요. Don't use it about close friends or younger family. With third-party adults, default to -시- — it's the polite choice. In service language ('the customer ___'), -시- is constant: 손님이 오셨어요 = 'a customer has come'.
Subject marker -이/가 → -께서
When you really want to mark honorifics fully, swap the subject particle -이/가 for -께서. 선생님께서 가세요. is the maximally respectful version of 'the teacher is going'. In casual respectful speech you'll often hear just 선생님이 가세요 (without -께서) — that's still polite. Use -께서 in formal writing or when speaking very respectfully. Similarly, the dative -에게 has an honorific cousin -께: 선생님께 드렸어요 = 'I gave (it) to the teacher'.
Putting it together — a service line
손님, 무엇을 드시겠어요? = 'Customer, what would you like to eat?' Pieces: -시- in 드시- (honorific 'eat') + -겠- (will/intent, lesson 24) + -어요 (polite). 잠시만 기다려 주세요. = 'Please wait a moment' — the 주세요 here is itself -(으)시- + ending. Korean service speech is wall-to-wall -시-; once you hear it, you can't unhear it.
