• By the end of this lesson, you will be constructing sentences using -아/어/여 [-a/eo/yeo] + -야 되다/하다 [-ya doe-da/ha-da] to say things such as “I have to go to work” or “You should buy it.”
• To use this ending, take the verb stem and add -아/어/여 PLUS -야 되다 or -야 하다.

Conjugasion:

verb stem + -아/어/여 + -야 되다/하다

1. verb stems ending in vowels ㅏ or ㅗ + -아야 되다/하다
2. verb stems ending in other vowels + -어야 되다/하다
3. 하 + -여야 되다/하다

Les exemples:

1. 자다 [ja-da] = to sleep

자 + -아/어/여 + -야 되다/하다→ 자 + -아 + -야 되다/하다(-아 is chosen because 자 ends with a vowel.)→ 자야 되다/하다 [ja-ya doe-da/ha-da]

(Drop the -아 because it is the same as ㅏ.)→ 자야 되다 and 자야 하다 are the same things.

1. 쓰다 [sseu-da] = to use; to write

쓰 + -아/어/여 + -야 되다/하다→ 쓰 + -어 + -야 되다/하다

(-어 is chosen because 쓰 does not end in ㅏ or ㅗ.)

→ 써야 되다/하다 [sseo-ya doe-da/ha-da] (쓰 + 어 together change to 써) → 써야 되다 and 써야 하다 mean the same thing.

However, it is more important to understand WHY -아/어/여야 되다/하다 means “to have to” or“should”.