peneuro pyeonjireul sseoyo.

I write a letter with a pen.

Breakdown of peneuro pyeonjireul sseoyo.

• ~을: object particle
• ~으로: instrumental particle
• 편지: letter
• 쓰다: to write
• 펜: pen

Questions & Answers about peneuro pyeonjireul sseoyo.

What is the function of -으로 in 펜으로?

-으로 is the instrument/means particle. It marks 펜 as the tool you’re using—so 펜으로 literally means “by/with a pen.”

When do you attach -으로 vs. -로?

• If a noun ends in a consonant (except ㄹ), you use -으로.
• If a noun ends in a vowel or in ㄹ, you use -로.
  Since 펜 ends in ㄴ, we use 펜으로.

Why is 편지를 marked with -를?

-를 (or -을) is the direct-object particle. It tells you that 편지 is what is being written—the target of the action.

Can you omit the object particle -를, and just say 편지?

In casual speech you might hear it dropped—펜으로 편지 써요—but including -를 is more natural and grammatical, especially in writing or formal contexts.

Why is the verb 써요 instead of 쓰다?

쓰다 is the dictionary (infinitive) form meaning “to write.” 써요 is the present-tense polite form, “(I/you/they) write.”

How would you change 써요 to other speech levels or tenses?

Here are a few variants:
• Formal polite present: 씁니다
• Polite past: 썼어요
• Polite future: 쓸 거예요
• Casual present: 써

Why is there no subject like 나 or 저 in the sentence?

Korean often drops the subject when it’s clear from context. You could say (저는) 펜으로 편지를 써요 to be explicit, but it’s not required.

Is the word order flexible? Could you say 편지를 펜으로 써요?

Yes. Korean typically follows S-O-V, but topical/object phrases can switch places for emphasis or style. 펜으로 편지를 써요 and 편지를 펜으로 써요 both mean “(I) write a letter with a pen.”