kanozyo ha byouki nanode, kyou ha kaisya ni ikimasen.

They are doing two different topic-like jobs.

• 彼女は = as for her
• 今日は = as for today / today, at least

Japanese can have a main topic and then a smaller, more local topic such as time, place, or contrast. So this sentence feels like:

• As for her, today she is not going to the office because she is sick.

The second は especially gives a slight sense of contrast, like today is the important time frame.

Because with a noun or na-adjective, ので connects using な, not だ.

• 病気 is a noun-like word here.
• Noun + なので is the correct pattern.

So:

• 病気なので = correct
• 病気だので = incorrect

A very polite version can also be:

• 病気ですので

But 病気なので is completely normal.

Because ので already connects the clause.

The sentence is not ending at 病気; it continues into a reason clause:

• 彼女は病気なので = because she is sick

If you want a more explicitly polite version, you can say:

• 彼女は病気ですので、今日は会社に行きません。

But in ordinary polite Japanese, 病気なので plus a polite ending later (行きません) is very common.

なので means because, since, or so.

It is similar to から, but the nuance is a little different:

• ので sounds softer, more explanatory, and often a bit more polite
• から sounds more direct and assertive

So:

• 病気なので、行きません。 = softer explanation
• 病気だから、行きません。 = more direct statement

Both are natural, but ので is very common when giving a reason politely.

Yes, it could just be 今日.

• 今日は会社に行きません。
• 今日会社に行きません。

Both are natural.

The version with は puts a little extra focus or contrast on today, as in:

• as for today
• today, though
• at least today

So the sentence may imply that going to work is normal in general, but today is different.

Because 行く usually takes に or へ to mark the destination.

• 会社に行く = go to the office/company
• 会社へ行く = go toward the office/company

Both are possible, but に is very common.

Do not use で here, because で marks the place where an action happens, not the destination of going.

Yes.

• 会社に行きません
• 会社へ行きません

Both mean do not go to the office.

The difference is small:

• に focuses more on the destination
• へ focuses more on direction toward that destination

In everyday speech, に is extremely common with 行く.

Because Japanese non-past forms cover both present and future.

• 行きます / 行きません can mean go / do not go or will go / will not go

The time word 今日 tells you how to interpret it. In this sentence, it naturally means:

• she is not going today
• she won’t go today

Japanese does not usually need a separate future tense the way English does.

No. 彼女 can mean:

• she / her
• girlfriend

Context decides which meaning is intended.

In this sentence, it is understood as she. But in real conversation, Japanese often avoids pronouns when they are already clear, so using 彼女 can sometimes sound more explicit than English she.

は marks 彼女 as the topic: the sentence is about her.

• 彼女は = as for her

If you used が, the focus would shift more strongly onto her as the specific person involved, often as new or contrastive information.

So in a neutral statement like this, は is the more natural choice.

Yes. Japanese word order is flexible as long as the particles stay attached to the right words.

For example, these are also possible:

• 今日は彼女は病気なので、会社に行きません。
• 彼女は今日は病気なので、会社に行きません。

The original order is natural because it sets up:

1. 彼女 as the main topic
2. 今日 as the time frame

So it sounds well organized and easy to follow.

No. Japanese commas are much more flexible than English commas.

The comma here simply helps show a pause and makes the sentence easier to read:

• 彼女は病気なので、今日は会社に行きません。

Without the comma, it is still correct:

• 彼女は病気なので今日は会社に行きません。

Writers often add commas where they feel a natural break.

Here are the common readings:

• 彼女 = かのじょ
• 病気 = びょうき
• 今日 = きょう
• 会社 = かいしゃ
• 行きません = いきません

A common point to notice is 今日, which is read きょう, not something fully predictable from the kanji alone.