kyou ha tyotto zizyou ga aru si, hayame ni kaerimasu

今日は sets today as the topic: as for today.

That does not mean today is the grammatical subject of the whole sentence. It just gives the time/topic frame for what follows.

So:

• 今日は = as for today / today
• then the speaker says what is true today:
  ちょっと事情があるし、早めに帰ります

This is very common in Japanese: time expressions are often followed by は when they are being contrasted with other times or presented as the topic.

They are doing different jobs:

• は in 今日は marks the topic
• が in 事情がある marks the subject of ある

So the structure is roughly:

• 今日は = as for today
• 事情がある = there are circumstances / I have circumstances

A natural way to think about it is:

• Today,
• there are some circumstances, so
• I’ll go home a bit early.

Even though English might use I more directly, Japanese often leaves the person unstated when it is obvious from context.

Literally, yes, ちょっと often means a little / a bit. But here it does more than that.

In this sentence, ちょっと softens 事情がある. It makes the statement less blunt and more natural in conversation.

So ちょっと事情がある feels like:

• I have a bit of a situation
• something has come up
• I have some personal circumstances

It often works as a politeness-softening word, not just a quantity word.

事情 means circumstances, situation, or reasons behind something.

In ちょっと事情がある, it usually suggests:

• there is some personal reason
• there are circumstances the speaker does not want to explain in detail
• the listener does not need the full story

So it is a vague and polite expression. It is often used when someone wants to say I have my reasons without being specific.

Because ある means to exist / to have in this kind of pattern, and the thing that exists is marked by が.

So:

• 事情がある = there are circumstances / I have reasons

This is similar to other common patterns:

• 時間がある = there is time / I have time
• 用事がある = there is something to do / I have an errand
• 問題がある = there is a problem

In Japanese, many things that English expresses with have are expressed with X がある.

し is often used to give a reason, especially in a conversational, slightly soft, less direct way.

Here it connects:

• ちょっと事情があるし
• 早めに帰ります

So the sense is:

• I’ve got some circumstances / something has come up, so I’m going home a bit early.

But し often carries a nuance like:

• for one thing...
• and besides...
• there are reasons...

It can sound softer and less rigid than a plain から or ので.

That is a very common question. Yes, し often lists multiple reasons:

• 安いし、おいしいし、よく行きます。
  It’s cheap, tasty, and I go there often.

But in real Japanese, し can also be used with just one stated reason.

When that happens, it often suggests one of these nuances:

• the speaker is being casual
• the speaker is softening the explanation
• the speaker may be leaving other reasons unstated
• the speaker does not want to sound too direct

So ちょっと事情があるし can feel like: I have my reasons, and... well, I’ll head home a bit early.

早め means somewhat early or earlier than usual, often with the nuance of on the early side.

So:

• 早く帰ります = I’ll go home early
• 早めに帰ります = I’ll go home a little earlier than usual / on the early side

早め is built from 早い plus め, which often adds the idea of somewhat / rather / on the ... side.

Examples:

• 多め = a bit more / on the generous side
• 少なめ = a bit less / on the lighter side
• 早め = a bit early / earlier than usual

Because 早めに is being used adverbially to describe how the speaker will go home.

• 早め = early side / somewhat early
• 早めに = early / a bit early / earlier than usual

This に is common when a noun-like or な-adjective-like form is used as an adverb.

Compare:

• 静かに話す = speak quietly
• 丁寧に説明する = explain carefully
• 早めに帰る = go home a bit early

Because the sentence is talking about what the speaker is going to do today.

Japanese non-past forms like 帰ります can mean:

• present habitual action, or
• future action, depending on context

Here, with 今日は and the overall meaning, it clearly means future:

• I’ll go home a bit early today.

If it were past, it would be:

• 早めに帰りました = I went home a bit early

The subject is omitted because it is understood from context.

In Japanese, if it is obvious who is being talked about, pronouns are often left out. In this sentence, the speaker is explaining their own action, so I is naturally understood:

• (I) have some circumstances, so (I) will go home a bit early.

This is extremely normal in Japanese.

Yes, very much so.

事情がある is a common expression meaning:

• to have circumstances
• to have one’s reasons
• to have a situation

It often implies that the speaker does not want to explain the details.

For example:

• ちょっと事情があって...
  Something came up... / I have some circumstances...

This is a very natural, polite, somewhat vague way to refer to personal reasons.

Because several parts of it soften the message:

• ちょっと softens the statement
• 事情がある is vague and avoids details
• し makes the reason sound less blunt and more conversational
• 帰ります is polite

So instead of saying something very direct like:

• 今日は理由があるから、早く帰ります。

the speaker says something softer and more natural:

• 今日はちょっと事情があるし、早めに帰ります。

This kind of indirectness is very common in polite Japanese.

Sometimes, but the nuance changes.

• 用事がある = I have something to do / I have an errand / I have plans
• 事情がある = I have circumstances / I have reasons / something personal is going on

用事 is more concrete and everyday.
事情 is vaguer and can sound more private or sensitive.

So:

• 今日はちょっと用事があるし、早めに帰ります。
  = I have something to do today, so I’m going home a bit early.

• 今日はちょっと事情があるし、早めに帰ります。
  = I have some circumstances today, so I’m going home a bit early.

The original sounds more like there are personal reasons I’d rather not go into.

Yes. In natural English, because is often the best translation.

Even though し is not exactly the same as から or ので, the overall meaning here is still causal:

• I have some circumstances, so/because I’m going home a bit early.

A very literal translation of し would not sound natural in English. So using because, so, or even something like I’ve got something going on, so... is perfectly normal.

Yes.

The politeness mainly comes from 帰ります, which is in the ます form.

Also, the overall phrasing is socially smooth:

• ちょっと softens
• 事情がある avoids oversharing
• し sounds conversational and gentle

So this would be natural in a workplace or other polite setting when explaining why you are leaving early.