naruhodo, sorede kyou ha hayaku kaerundesu ne.

なるほど is an interjection that shows the speaker has just understood something. It is like saying:

• I see.
• That makes sense.
• Oh, right.

It does not add core grammar to the sentence; it sets the speaker’s reaction. In this sentence, it shows the speaker is connecting what they just heard with the conclusion that follows.

Here, それで means something like:

• so
• and because of that
• that’s why

It links the previous information to the current conclusion. In this sentence, the flow is:

1. なるほど = I understand.
2. それで = so / that explains why...
3. the rest of the sentence = the conclusion

So それで is not just a simple and then here. It is more about cause/result or explanation.

今日は makes today the topic of the sentence.

So the sentence is not just saying today as a time word. It is more like:

• As for today,
• today in particular,

This can give a slight contrastive nuance too, depending on context:

• maybe today is different from other days
• maybe the person does not usually go home early

So 今日は can feel like as for today, you’re going home early.

Because 早い is an -i adjective, and when you use it to modify a verb, it changes to its adverb form.

• 早い = early / fast
• 早く = early / quickly

Since 帰る is a verb, you need the adverb form:

• 早く帰る = to go home early

Using 早い directly before 帰る would be wrong here.

This is because んです attaches to the plain form of a verb.

So:

• plain form: 帰る
• explanatory form: 帰るんです

You cannot say 帰りますんです.

Also, 帰るんです is still polite because of です at the end. This is a very common pattern in Japanese: plain verb + んです.

んです adds an explanatory or contextual tone. It often suggests:

• giving a reason
• explaining a situation
• connecting to something already being discussed
• softening the statement by presenting it as something understandable in context

So 帰るんです is not just go home. It feels more like:

• (I see,) so you’re going home early
• (That explains it,) you’re going home early
• it’s that you’re going home early

In this sentence, んです fits very naturally because the speaker has just realized or understood something.

Sentence-final ね asks for shared understanding or shows the speaker expects agreement. It can feel like:

• right?
• isn’t that so?
• I see, huh.

Here, ね makes the sentence softer and more interactive. The speaker is not just stating a fact flatly; they are showing that they have understood and are lightly confirming it with the other person.

Without ね, the sentence would sound more direct and less conversational.

Grammatically, it is often treated as a statement with a confirming tone, but in conversation it can sound a bit question-like depending on intonation.

With natural speech, it can mean something like:

• I see, so you’re going home early today, right.
• Oh, I get it—so that’s why you’re going home early today?

The final ね is the reason it can sound like soft confirmation rather than a plain statement.

So it is best understood as a confirming / understanding statement, not a strong direct question.

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

So 帰るんです could refer to:

• you are going home early
• he/she is going home early
• they are going home early
• sometimes even I am going home early

In a real conversation, the listener knows who is being talked about from the situation. Japanese does this very often, so omitted subjects are normal.

Because です does not attach directly to a plain verb like that.

• 帰るです = incorrect
• 帰ります = correct polite verb form
• 帰るんです = correct explanatory/polite form

When you want to use です after a verb in this explanatory way, you need のです / んです.

So 帰るんです is the correct structure.

んです is just a contracted, more natural spoken form of のです.

• 帰るのです = more formal, stiffer
• 帰るんです = more natural in everyday speech

In normal conversation, んです is much more common. A learner should recognize that both are the same basic grammar point.

Sometimes yes, but the nuance changes.

• それで connects to what was just said and often sounds like so / and that’s why
• だから is more directly therefore / so

In this sentence, なるほど、それで... is very natural because the speaker is reacting to new information and drawing a conclusion from it. だから could sound a bit stronger or more assertive, while それで flows more gently from the previous statement.

Those spaces are almost certainly just for learning purposes. Normal Japanese writing does not usually put spaces between words like this.

A normal written version would be:

なるほど、それで今日は早く帰るんですね。

Textbooks and study materials sometimes add spaces to help learners see the parts more clearly.