In the following series, I will introduce you to many different verbs. We will learn the common verbs in the infinitive form. Learning the Korean infinitive is important because the infinitive has a great many uses of its own, and in addition it is what the past tense is based on.
Verbs in the Infinitive Form
Korean verb forms are made up of BASES with ENDINGS on them.
For example:
좋아요 = is good
없어요 = is nonexistent
These are in present-tense forms and both are in the Polite Style and have the marker 요 at the end to mark the style. If you remove this 요, the part that remains is called the INFINITIVE of the verb.
In other words, verbs in the INFINITIVE forms are forms that has the 요 removed from the polite form. They’re used as the standard sentence ending verb in the non-polite form or 반말.
For example,
좋아요. If you remove 요 then it will be 좋아
없어요 If you remove 요 then it will be 없어
좋아요 >>> 좋아
없어요 >>> 없어
NOTE:
Do not mix it with the English infinitive. The Korean word ‘infinitive’ or 동사 원형 (Original Verb Form) does NOT mean the same thing as when we talk about English. ‘Infinitive’ is just a term or a name for the ~어 ~아 ending in Korean. Learning the infinitive form of the verb in Korean language is important since it is in the form of a conversation.
Bases of Korean verbs are classified into two main types: CONSONANT BASES and VOWEL BASES. For those Korean learners who are asking what is a ‘base’? Let’s do a quick refresher on the base or verb stem, the meaning of the dictionary form of Korean verbs, and the meaning of bright vowels and dark vowels.
Alright, let’s start with the dictionary form. Korean dictionaries list verbs in a special dictionary form with the ending ~다. This ending is the same for all verbs, and is NOT an infinitive. For example, 보다 and 먹다.
Verb stem or the base is erasing ~다 at the end of the dictionary form. For example, just 보 from 보다 and 먹 from 먹다. Remember that these verb stems are never used by itself.
In Korean, bright vowels are ㅏ/ㅗ vowels and dark vowels are ㅓ/ㅜ vowels.
Korean Verbs with Consonant Bases
Now, there are some rules to follow in deriving the infinitive form and this starts by identifying the base form of the verb. Consonant-base verbs typically have the infinitive ending ~어 and their infinitives consist of the base plus this vowel ending ~어. However, if the last vowel of the base is ㅗ or ㅏ then the ending is ~아 instead of ~어.
In other words, all consonant ending base verbs ends with ~어, the only exception is if the preceding vowel is ㅗ or ㅏ the ending would be ~아.
For example,
찾다. What is the base? Just erase ~다 and the base is 찾. 찾 ends with the consonant ㅈ so it is a consonant ending base verb. Also, 찾 ends with a vowel ㅏ [아 vowel]. Since the last vowel of the base is a bright vowel ㅏ, the ending would be ~아. Hence, 찾아 finds.
Another example is 먹다. What is the base? Just erase ~다 and the base is 먹. 먹 ends with the consonant ㄱ so it is a consonant ending base verb. Also, 먹 ends with a vowel ㅓ [어 vowel]. Since the last vowel of the base is a dark vowel ㅓ, the ending would be 어. Hence, 먹어 eats.
Let’s go over a list of some consonant bases and infinitives:
| Base | Infinitive Form | ||
| 앉- | sit | 앉아 | sits |
| 작- | be little in size | 작아 | is little in size |
| 입- | wear; put on | 입어 | wears; puts on |
| 좋- | be good | 좋아 | is good |
| 없- | be nonexistent | 없어 | is nonexistent |
| 읽- | read | 읽어 | reads |
| 있- | be, exist; stay; have | 있어 | is, exists; stays; has |
| 많- | be much/many | 많아 | is much; are many |
| 받- | receive, get | 받아 | receives, gets |
| 닫- | close it | 닫아 | closes it |
| 들- | listen to; hear | 들어 | listens to; hears |
| 더w- | be hot | 더워 | is hot |
| 나(ㅅ)- | get/be better | 나아 | gets/is better |
Did you notice that all of the infinitives end in a vowel 어 or 아?
Also, notice that the translation of infinitives by English forms like ‘sits’ instead of ‘to sit’. It is because the Korean forms can be used as sentences just as they stand. In other words, verbs in infinitive form can be used in a conversation as if it’s a complete sentence. These sentences are in the ‘Casual Style’ since the polite-style marker 요 has been removed.
For example,
가: 앉아
A: Sit
Three Types of Special Consonant Base
The only tricky point to remember about consonant-base verbs concerns the following three bases.
들- which means listen to
더w – which means be hot
나(ㅅ) – which means get/be better
1. ㄹ ~ ㄷ verbs
Verbs that end in ~ㄹ change the ~ㄹ to ㄷ before endings that begin with a consonant: For example:
들~ listen to >>> 듣다 to listen to (Dictionary form)
2. w ~ ㅂ verbs
Verbs that end in -w change the -w to ㅂ before endings that begin with a consonant: For example,
더 w- be hot >>> 덥다 to be hot (Dictionary form)
3. S-irregular Verbs
Verbs that end in (ㅅ) drop the ㅅ before endings that begin with a vowel: For example:
나 (ㅅ) – be better >>> 나아 is better (Infinitive form)
>>> 낫다 to be better (Dictionary form)
These are different from regular verbs in ㅅ[시옫], which keeps the ㅅ in all forms:
벗 ~ take off (clothes) >>> 벗어 takes off (clothes) [infinitive form]
>>> 벗다 to take off (clothes) [dictionary form]
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