LEARN KOREAN (한국어) [GRAMMAR] #1

CONJUGATING 이다

이다 is conjugated differently than other verbs/adjectives. Not just when conjugating, but when doing other things to 이다, it usually behaves in another way. As of now, the only conjugation you know for 이다 is the plain form in the present tense:

나는 선생님이다 - I am a teacher

If the last letter of the noun before 이다 ends in a vowel, you can eliminate 이. For example:

나는 의사다 - I am a doctor
나는 의사이다 - I am a doctor

Both of the above can be seen as correct. Here, the pronunciation of "이" is merging with the pronunciation of the vowel in the noun. If you pronounce the two sentences above, you can see that there is very little difference.

Conversely, if the last letter of the noun before 이다 is a consonant, this merging cannot happen. For example:

나는 선생님이다 - I am a teacher (correct)
나는 선생님다 – incorrect

This merging of 이다 does not happen because it has nothing to merge with. Furthermore, if you try to pronounce "선생님다", it just doesn't flow properly. It is hard to get your mouth to move from the "ㅁ" sound immediately to the "ㄷ" sound. This same principle occurs in other conjugations of 이다, but it is a little bit more complex.

In almost every case, you can conjugate 이다 differently depending on if the noun it is being attached to ends in a vowel or consonant. The reason they are conjugated differently is similar to the example above with 의사다 vs. 의사이다. Here, the pronunciation of "이" is being merged with something, and can therefore disappear. You will learn about each conjugation specifically, but I will give you an example here to prepare you for all the future explanations. Try not to worry about the meanings of these sentences, and just focus on what I am presenting.

When conjugating 이다 into the past tense in the plain form, "었다" is added to the stem of "이다" (이). This is actually quite simple for you to understand, because every other verb and adjective follows this same rule. For example:

의사이었다
선생님이었다

However, the pronunciation of 이었다 can merge to "였다" when the noun that it is being attached to ends in a vowel. For example, both of these are correct:

의사이었다
의사였다

Pronounce both of those, and listen to how little of a difference there is between the two. Not only that, the pronunciation of both of those is very easy and it flows off the tongue.

Conversely, 이 and 었다 cannot merge when the noun it is added to ends in a consonant. For example:

선생님이었다 – correct
선생님였다 – incorrect

Pronounce both of those and listen the difference. Not only that,'선생님였다' is hard to pronounce. It is difficult to move your mouth from the ㅁ sound directly to the 여 sound. It is much easier to pronounce it like this: 나는 선생님-이-었-다.

Although I am only talking about the past tense plain form in this example, this same rule applies in many situations. If you keep this in mind when learning the conjugations in this lesson, they will be much easier to grasp.