balpyo yeonseup yeongsangeul dasi pyeonjiphamyeonseo bareumeul hanassik gochyeosseo.

A natural breakdown is:

• 발표 연습 영상 = presentation practice video
• -을/를 → 영상을 = marks 영상 as the object
• 다시 = again
• 편집하면서 = while editing
• 발음을 = pronunciation + object marker
• 하나씩 = one by one
• 고쳤어 = corrected/fixed

So structurally, it is:

[발표 연습 영상을 다시 편집하면서] [발음을 하나씩 고쳤어].

That means:

• while re-editing the presentation practice video,
• I corrected the pronunciation one by one.

It is a noun phrase made of three nouns:

• 발표 = presentation
• 연습 = practice
• 영상 = video

Together, 발표 연습 영상 means something like:

• a video for practicing a presentation
• a presentation practice video
• a video of presentation practice

Korean often stacks nouns like this without extra words like for, of, or to. English usually needs those linking words, but Korean often does not.

-을/를 is the object marker.

• 영상 ends in a consonant, so it takes -을
• 영상 + 을 → 영상을

Here, 영상을 is the object of 편집하면서 from the verb 편집하다 (to edit).

So:

• 영상을 편집하다 = to edit a video

Even though 편집하면서 is not the final verb of the whole sentence, it still keeps its own object.

Because there are really two verb ideas in the sentence:

1. 영상을 다시 편집하면서
   = while re-editing the video

2. 발음을 하나씩 고쳤어
   = corrected the pronunciation one by one

So each verb has its own object:

• 영상 is the object of 편집하다
• 발음 is the object of 고치다

This is very common in Korean when one clause is connected to another.

-면서 means while doing, as, or at the same time as.

Here:

• 편집하다 = to edit
• 편집하면서 = while editing

So the sentence means that the speaker corrected the pronunciation during the process of re-editing the video.

A very important point: -면서 usually implies that the subject of both actions is the same.

So this sentence naturally means:

• I was re-editing the video
• and I corrected the pronunciation

Not:

• someone else edited it while I corrected it

Not always in a perfectly literal second-by-second sense.

In many sentences, -면서 means that one action happens in the course of another action. Here, it does not have to mean:

• editing one frame
• and correcting one sound
• at the exact same instant

Instead, it means more naturally:

• during the process of re-editing the video, I corrected the pronunciation

So it can express overlap in a broader sense, not just strict simultaneity.

다시 means again.

So:

• 편집하다 = to edit
• 다시 편집하다 = to edit again, re-edit

That is why 다시 편집하면서 means:

• while editing again
• more naturally in English, while re-editing

하나씩 means one by one or one at a time.

It comes from:

• 하나 = one
• -씩 = each / at a time / by increments

So 하나씩 gives the feeling of dealing with things individually.

In this sentence, 발음을 하나씩 고쳤어 means something like:

• I corrected the pronunciations one by one
• I fixed each pronunciation individually

Even though 발음 is singular in form, Korean often uses singular-looking nouns in places where English might prefer a plural idea. So in natural English, you may translate it as:

• I corrected the pronunciations one by one

Korean often does not mark plural when English would.

• 발음 can mean pronunciation in a general sense
• depending on context, it can also refer to multiple pronunciation issues

Because the sentence includes 하나씩, we understand that multiple items are being corrected one by one. So English often sounds more natural with a plural:

• I corrected the pronunciations one by one

But Korean does not need to say 발음들 here. In fact, 발음들 would often sound unnecessary.

Yes. 고치다 means:

• to fix
• to correct
• to revise

In this sentence, 고쳤어 means corrected or fixed.

So 발음을 고쳤어 means:

• corrected the pronunciation
• fixed the pronunciation

This does not mean repairing something physical. It means improving or correcting mistakes in pronunciation.

Also:

• 고쳤어 is the casual past form of 고치다

고쳤어 is casual/informal speech.

It is used with:

• close friends
• younger people
• people you speak casually with
• diary-style narration

More polite versions would be:

• 고쳤어요 = polite informal
• 고쳤습니다 = formal

So the sentence could become:

• 발표 연습 영상을 다시 편집하면서 발음을 하나씩 고쳤어요.

Same meaning, just more polite.

Korean often leaves the subject out when it is clear from context.

So even though the sentence does not explicitly say 나는 or 제가, the natural interpretation is:

• I corrected the pronunciation one by one while re-editing the presentation practice video.

This omission is extremely normal in Korean. If the speaker is obviously talking about their own actions, the subject is usually not stated.

Primarily it describes the situation/process in which the second action happened.

It can feel like:

• while re-editing the video
• in the course of re-editing the video
• as I was re-editing the video

Depending on context, English might slightly reinterpret it as:

• timing: while
• process: during the process of
• means/opportunity: by re-editing / while going through the video again

So it mainly gives background for how the speaker came to correct the pronunciation.

Yes, the sentence can allow a couple of closely related interpretations depending on context.

Possible readings include:

1. While re-editing the practice video, I corrected pronunciation issues one by one.
   This could mean noticing and fixing spoken errors.

2. While re-editing the practice video, I corrected the pronunciation one by one in the recording/edit.
   This could suggest working on the video/audio itself.

Most naturally, though, many learners would understand it as the speaker going through the recording and addressing pronunciation problems individually.

So context would decide whether the emphasis is on:

• improving their speaking,
• correcting recorded segments,
• or both.

You could, but the nuance changes.

• 편집하면서 = while editing / during editing
• 편집하고 = edited and / after editing / and then edited, depending on context

With -면서, the focus is on overlapping or accompanying actions.

With -고, the actions are just connected in sequence or loosely linked.

So:

• 발표 연습 영상을 다시 편집하면서 발음을 하나씩 고쳤어
  = While re-editing the video, I corrected the pronunciation one by one.

• 발표 연습 영상을 다시 편집하고 발음을 하나씩 고쳤어
  = I re-edited the video and corrected the pronunciation one by one.

The original sentence sounds better if the idea is that the corrections happened during the re-editing process.

Because Korean usually puts descriptive nouns before the main noun.

In 발표 연습 영상:

• 영상 is the main noun
• 발표 연습 describes what kind of video it is

English often needs linking words:

• video for presentation practice
• video of presentation practice

Korean usually just stacks the nouns together and lets context explain the relationship.

That is why Korean noun phrases can feel very compact compared with English.