How do you write friend in Korean writing?

"Friend" in Korean can be written in two ways, depending on the level of formality:

Formal: 친구 (chingu)

Informal: 친구 (chingu)

It's interesting to note that the spelling is the same, but the pronunciation is slightly different depending on the context.

* Formal: Pronounced with a slightly more formal tone and emphasis on the "u" sound in "chingu". This would be used for someone older than you or someone you don't know well.

* Informal: Pronounced with a more casual tone and emphasis on the "i" sound in "chingu". This would be used for close friends or people your own age.

So, you would use "친구" (chingu) for both formal and informal contexts, but the pronunciation would differ depending on the situation.