Expressing Ability with 'ㄹ 수 있다'

01

Forming the Structure

The first step is attaching the correct suffix to the verb stem. This depends on whether the stem ends in a vowel or a consonant.

• Vowel-ending stems: Attach ㄹ (l) directly to the bottom of the verb stem, followed by 수 있다 (su it·dasu it·dasu it·dasu it·ta).

• 저는 한국어를 할 수 있어요.

  jŏ·nŭn han·gu·gŏ·rŭl hal su iss·ŏ·yo.jeo·neun han·gu·geo·reul hal su iss·eo·yo.jŏ·nŭn han·gu·gŏ·rŭl hal su iss·ŏ·yo.ce·nun han·ku·ke·lul hal su iss·e·yo.

  I can speak Korean.

• Consonant-ending stems: Add 을 (ŭleulŭlul) after the stem, followed by 수 있다 (su it·dasu it·dasu it·dasu it·ta).

• 이 책을 읽을 수 있어요.

  i chæ·gŭl il·gŭl su iss·ŏ·yo.i jae·geul il·geul su iss·eo·yo.i chae·gŭl il·gŭl su iss·ŏ·yo.i cay·kul il·kul su iss·e·yo.

  I can read this book.

• Stems ending in ㄹ: If the stem already ends in ㄹ (l) (like 살다 (sal·dasal·dasal·dasal·ta), to live), the ㄹ (l) remains and you simply add 수 있다 (su it·dasu it·dasu it·dasu it·ta). You do not add an extra 을 (ŭleulŭlul).

• 여기서 살 수 있어요.

  yŏ·gi·sŏ sal su iss·ŏ·yo.yeo·gi·seo sal su iss·eo·yo.yŏ·gi·sŏ sal su iss·ŏ·yo.ye·ki·se sal su iss·e·yo.

  I can live here.

02

Expressing Inability (Cannot)

To say that you cannot do something, replace 있다 (it·dait·dait·dait·ta) (exists) with 없다 (ŏp·daeop·daŏp·daep·ta) (does not exist). The conjugation rules for the verb stem remain exactly the same.

• 저는 수영할 수 없어요.

  jŏ·nŭn su·yŏng·hal su ŏps·ŏ·yo.jeo·neun su·yeong·hal su eops·eo·yo.jŏ·nŭn su·yŏng·hal su ŏps·ŏ·yo.ce·nun su·yeng·hal su eps·e·yo.

  I cannot swim.

• 매운 음식을 먹을 수 없어요.

  mæ·un ŭm·si·gŭl mŏ·gŭl su ŏps·ŏ·yo.mae·un eum·si·geul meo·geul su eops·eo·yo.mae·un ŭm·si·gŭl mŏ·gŭl su ŏps·ŏ·yo.may·un um·si·kul me·kul su eps·e·yo.

  I cannot eat spicy food.

03

Ability vs. Possibility

This grammar point covers two distinct concepts in English: skill and circumstance.

1. Skill / Capability

It expresses that someone has learned a skill or has the physical capacity to perform an action.

• 피아노를 칠 수 있어요?

  pi·a·no·rŭl chil su iss·ŏ·yo?bi·a·no·reul jil su iss·eo·yo?pi·a·no·rŭl chil su iss·ŏ·yo?pi·a·no·lul cil su iss·e·yo?

  Can you play the piano?

2. Possibility / Circumstance

It expresses that the current situation allows for an action to happen, even if the skill is not the focus.

• 지금 통화할 수 있어요?

  ji·gŭm tong·hwa·hal su iss·ŏ·yo?ji·geum dong·hwa·hal su iss·eo·yo?ji·gŭm tong·hwa·hal su iss·ŏ·yo?ci·kum tong·hwa·hal su iss·e·yo?

  Can you talk on the phone right now?

• 내일 갈 수 없어요.

  næ·il gal su ŏps·ŏ·yo.nae·il gal su eops·eo·yo.nae·il gal su ŏps·ŏ·yo.nay·il kal su eps·e·yo.

  I cannot go tomorrow.

04

Conjugating the Final Verb

Since the phrase ends with the adjectives 있다 (it·dait·dait·dait·ta) or 없다 (ŏp·daeop·daŏp·daep·ta), you must conjugate these words according to the politeness level required by the situation.

• Polite Style (Standard): Use 있어요 (iss·ŏ·yoiss·eo·yoiss·ŏ·yoiss·e·yo) or 없어요 (ŏps·ŏ·yoeops·eo·yoŏps·ŏ·yoeps·e·yo). This is most common in daily conversation.
• Formal Style: Use 있습니다 (iss·ŭm·ni·daiss·eum·ni·daiss·ŭm·ni·daiss·um·ni·ta) or 없습니다 (ŏp·sŭm·ni·daeop·seum·ni·daŏp·sŭm·ni·daep·sum·ni·ta). This is used in presentations, news, or very formal settings.
• Casual Style: Drop the 요 (yo) to form 있어 (iss·ŏiss·eoiss·ŏiss·e) or 없어 (ŏp·sŏeop·seoŏp·sŏep·se). This is used only with close friends or those younger than you.

• 운전할 수 있습니다.

  un·jŏn·hal su iss·ŭm·ni·da.un·jeon·hal su iss·eum·ni·da.un·jŏn·hal su iss·ŭm·ni·da.un·cen·hal su iss·um·ni·ta.

  I can drive. (Formal)

• 이거 할 수 있어?

  i·gŏ hal su iss·ŏ?i·geo hal su iss·eo?i·gŏ hal su iss·ŏ?i·ke hal su iss·e?

  Can you do this? (Casual)