LEARN KOREAN (한국어) [GRAMMAR] #1

IRREGULARS

As with all languages, there are some irregular conjugations that you need to know. Irregulars are applied to certain verbs or adjectives when adding something to the stem of the word. Korean grammar is based on these "additions" that are added to stems.

There are hundred of additions that you can add to the stem of a verb or adjective. Some of these additions are conjugations and some of them are grammatical principles that have meaning in a sentence.

You have learned about some of these additions now. For example:
•ㄴ/는다 to conjugate to the plain form
•아/어 to conjugate to the informal low respect form
•아/어요 to conjugate to the informal high respect form
•ㅂ/습니다 to conjugate to the formal high respect form
•았/었어 to conjugate to the informal low respect form in the past tense
•ㄴ/은 added to an adjective to describe an upcoming noun

You will learn about many more of these additions. For exanple, some of them are:
•ㄴ/은 후에 to mean "after"
•기 전에 to mean "before"
•기 때문에 to mean "because"
•아/어서 to mean "because"
•(으)면 to mean "when"
•아/어야 한다 to mean "one must"
•아/어서는 안 되다 to mean "one should not"
Notice that some of these additions start with a vowel, and some of them start with a consonant. Most of the irregulars are applied when adding a vowel to a stem. The ㄹ irregular is the only irregular that applies when adding a consonant to a stem.

Let's look at one example. Let's say we want to conjugate the word 어렵다 into the past tense using the informal low respect form. The following would happen:

어렵다 + 았/었어 = 어려웠어

Here, you can see that actual stem of the word changed. This is referred to as the "ㅂ irregular" because the same phenomenon happens with many (but not all) words whose stem ends in ㅂ.

As I mentioned previously, most of these irregulars are applied when adding a vowel to a stem. There are many additions that start with a vowel, and you got a start on learning some of those conjugations:
•아/어
•아/어요
•았/었어
•았/었어요
•았/었습니다
•았/었다