ganjangeul neomu manhi neoheumyeon gugi jjajyeoyo.

간장 means soy sauce.

The -을 at the end is the object particle, so 간장을 means soy sauce as the thing being added.

So:

• 간장 = soy sauce
• 간장을 = soy sauce + object marker

Because 간장 is the thing that receives the action of 넣다 (to put in / add).

In this sentence, someone is adding soy sauce, so 간장 is the object.

Compare:

• 간장을 넣다 = to add soy sauce
• 물을 넣다 = to add water
• 설탕을 넣다 = to add sugar

너무 많이 means too much or more literally too a lot.

Breakdown:

• 너무 = too, excessively
• 많이 = a lot, much, in large quantity

Here 많이 is an adverb, so it modifies the verb 넣으면:

• 많이 넣다 = to add a lot
• 너무 많이 넣다 = to add too much

Even though English uses much here, Korean naturally uses 많이.

넣으면 comes from 넣다, which means to put in or to add.

The ending -으면 means if or when.

So:

• 넣다 = to add
• 넣으면 = if you add / when you add

In this sentence, 넣으면 connects the cause and the result:

• 간장을 너무 많이 넣으면 = if you add too much soy sauce

Korean uses:

• -으면 after a stem ending in a consonant
• -면 after a stem ending in a vowel

The verb stem here is 넣-, which ends in a consonant sound in spelling, so it takes -으면.

Examples:

• 먹다 → 먹으면 = if you eat
• 읽다 → 읽으면 = if you read
• 가다 → 가면 = if you go
• 보다 → 보면 = if you see

So 넣다 → 넣으면 is the regular pattern.

Because 국 is the subject of the result clause.

The soup is the thing that becomes salty, so Korean marks it with the subject particle 이.

• 국이 짜져요 = the soup gets salty

If you used 국을, it would make soup the object of some action, which does not fit this verb phrase.

So the structure is:

• If you add too much soy sauce,
• the soup gets salty

짜져요 means becomes salty or gets salty.

It comes from:

• 짜다 = to be salty
• -아/어지다 = to become

So:

• 짜다 = is salty
• 짜지다 = become salty
• 짜져요 = polite present form of 짜지다

This is why the sentence talks about a change of state: the soup was not salty enough before, and then it becomes salty.

You could say 국이 짜요, but it means the soup is salty.

The sentence uses 짜져요 instead because it emphasizes the result of adding too much soy sauce.

So the difference is:

• 국이 짜요 = the soup is salty
• 국이 짜져요 = the soup becomes salty / gets salty

In this sentence, 짜져요 is more natural because the first clause causes the second.

It can mean either if or when, depending on context.

In this sentence, it expresses a general cause-and-effect idea, so English often translates it as if:

• If you add too much soy sauce, the soup gets salty.

But it can also feel like when(ever) in the sense of a general rule:

• When you add too much soy sauce, the soup gets salty.

So both ideas are possible, but if is usually the most natural translation for learners.

Yes. Korean often leaves out the subject when it is obvious or not important.

Here, the sentence does not explicitly say you, but the meaning is understood as something like:

• if you add too much soy sauce
• if someone adds too much soy sauce
• if one adds too much soy sauce

This kind of omission is very common in Korean.

Korean word order is different from English, and the verb usually comes at the end of each clause.

A rough breakdown is:

• 간장을 = soy sauce
• 너무 많이 = too much
• 넣으면 = if you add
• 국이 = soup
• 짜져요 = gets salty

So the literal order is roughly:

• Soy sauce too much add-if, soup gets salty.

Natural English rearranges that to:

• If you add too much soy sauce, the soup gets salty.

This is a very normal Korean sentence pattern:

• cause/condition + result