르 irregular verbs: 르 → ㄹㄹ pattern

This grammar rule is like a chemical reaction. It only triggers when a specific ingredient is added. That ingredient is a suffix starting with a vowel. Usually, this means the -아/어 endings used in polite speech. When a 르 verb meets these vowels, it changes. The ㅡ vowel in 르 completely disappears. In its place, a new ㄹ is born. This new ㄹ jumps to the previous syllable. It acts as a final consonant (받침) there. The original 르 then transforms into either 라 or 러. This depends on the vowel harmony of the word. It sounds complicated, but it is just a dance. The ㄹ simply wants to be in two places. It wants to end one syllable and start another. This creates a smooth, flowing sound when you speak. It is much easier to say than the original form.

1. 1Let's break the conjugation into four easy steps. We will use the verb 모르다 (to not know).
2. 2Start with the verb base: 모르다.
3. 3Remove the 다 to find the stem: 모르.
4. 4Add a ㄹ to the bottom of the first syllable: 모 becomes 몰.
5. 5Change the 르 based on the vowel in the first syllable.
6. 6If the first vowel is ㅏ or ㅗ, use 라.
7. 7For all other vowels, use 러.
8. 8Let’s apply this to 모르다. The first vowel is ㅗ. So we add ㄹ to 모 to get 몰. Then we change 르 to 라. The final result is 몰라. Add 요 for the polite form: 몰라요.
9. 9Now let’s try 부르다 (to call/sing). The first vowel is ㅜ. We add ㄹ to 부 to get 불. Since ㅜ is not ㅏ or ㅗ, we use 러. The final result is 불러. Add 요 for the polite form: 불러요. It is like a grammar traffic light. Red for ㅏ/ㅗ, green for everything else.

You use this rule whenever you conjugate 르 verbs. This happens in the present tense with -아/어 요. It also happens in the past tense with -았/었 어요. You will use it when connecting sentences with -아/어 서.

Imagine you are at a karaoke room (노래방). You want to sing a song. You use the verb 부르다. You say, "노래를 불러요."

Imagine you are shopping in Seoul. You need to choose a gift. You use the verb 고르다 (to choose). You say, "선물을 골라요."

Imagine you are late for a meeting. You need to describe the fast train. You use 빠르다 (to be fast). You say, "기차가 빨라요."

These are all real-world, everyday situations. This rule is not just for textbooks. It is for your life in Korea. Even native speakers find these verbs very satisfying to say.

This rule is quite shy. It stays hidden when meeting consonants. If your grammar ending starts with a consonant, stop. Do not change anything. Just drop 다 and add the ending.

For example, use -고 to connect two actions. 모르다 simply becomes 모르고. No extra ㄹ is needed here.

Use -지만 to say "but." 빠르다 becomes 빠르지만. It stays perfectly regular.

Use -습니다 for very formal situations. 부르다 becomes 부릅니다. The 르 stays exactly where it is.

Think of the vowel as a key. Only the vowel key unlocks the irregular change. Without that key, the verb stays in its cage. This makes your job much easier sometimes. You only need to worry about the change half the time.

The biggest mistake is forgetting the extra ㄹ. Many people say 모라요 instead of 몰라요. This sounds very strange to Korean ears. It sounds like a missing tooth in a smile. Always remember to double that ㄹ.

Another mistake is picking the wrong vowel. Some say 몰러요 instead of 몰라요. Remember the ㅏ/ㅗ rule strictly. It is the same rule used for basic verbs. If you know 아요/어요, you know this.

Don't apply this to every verb ending in 다. Only verbs that actually have 르 right before 다.

Some people try to use this with 따르다 (to follow). But 따르다 is a rebel. It follows the ㅡ irregular rule, not the 르 rule. It becomes 따라요, not 딸라요. Yes, even grammar has its little tricksters. Just keep an eye out for them.

You might confuse this with the 러 irregular. The 러 irregular is very rare. It only applies to a few words like 이르다 (to arrive). In that case, it becomes 이르러요. Notice how the 르 stays and adds an extra 러.

Compare this to our 르 irregular. In our rule, the 르 disappears and splits. 모르다 becomes 몰라요.

Also, compare it to regular ㅡ verbs. Take 쓰다 (to write). It becomes 써요. There is no extra ㄹ because there was no ㄹ to begin with.

The 르 irregular is unique because of that double ㄹ. It creates a very distinct "L" sound. It is like the difference between "silly" and "silly" in English. Wait, that's the same. It's more like "pole" vs "polly." The double sound is key.