Learn Hardcore Japanese: kongetu ha sigoto ga totemo isogasii desu.

今月は literally means "As for this month," or "Speaking about this month,".
It sets 今月 (this month) as the background frame of what you are going to say.
The main comment about that topic is 仕事がとても忙しいです ("the work is very busy").

So the sentence is structured like:

Topic: 今月は → "This month (as for this month)…"
Comment: 仕事がとても忙しいです → "Work is very busy."

That’s why a natural translation is "Work is very busy this month."

Why is it 仕事が and not 仕事は?

In 仕事がとても忙しいです, the が marks 仕事 as the grammatical subject, and 忙しい is its state.

仕事が忙しい = "(the) work is busy."
が often highlights the thing that has the state described by the adjective.

If you used 仕事は, you would make 仕事 the topic instead, which subtly changes what you’re emphasizing:

今月は仕事が忙しいです。
- Topic: 今月 (this month)
- Focus: 仕事が忙しい (it’s work that is busy)
今月は仕事は忙しいです。
- Topic: 今月 (this month)
- Subtopic/emphasis: 仕事
- Implies a contrast, like: "This month, as for work, it’s busy" (but maybe something else is not).

So 仕事が is the most natural here because you are simply stating the situation: "Work is busy (this month)."

Where is "I" in this sentence? Why isn’t there a word for "I"?

Japanese often omits the subject when it’s clear from context.

In English, we must say "I am very busy with work this month."
In Japanese, if it’s obvious we’re talking about the speaker’s own situation, you don’t need to say 私 ("I").

So:

今月は仕事がとても忙しいです。
Literally: "As for this month, work is very busy."
Naturally understood as: "I’m very busy with work this month."

If you really want to include "I", you could say:

私は今月、仕事がとても忙しいです。
= "As for me, this month, work is very busy."

But usually 私は is omitted unless there’s a reason to stress who you’re talking about.

What exactly does とても mean? Are there similar words?

とても is an adverb that means "very" or "really."

忙しい = busy
とても忙しい = very busy / really busy

It’s neutral and polite and works well in most situations.

Similar expressions:

すごく忙しい – very/really busy (more casual, a bit like "super busy")
とっても忙しい – very/really busy (cute, casual, slightly emphatic)
かなり忙しい – quite/fairly busy (a bit more measured)
めっちゃ忙しい – extremely busy (very casual/slangy; Kansai-ish but common)

In polite, everyday conversation, とても忙しいです is safe and natural.

Why do we need です after an adjective like 忙しい? Isn’t 忙しい already "busy"?

You’re right that 忙しい by itself already means "busy."

However:

忙しい by itself is in a plain form, used in casual speech, writing, or dictionary form.
忙しいです adds です, which:
- makes the sentence polite,
- softens the tone.

So:

今月は仕事がとても忙しい。
→ casual: "Work is really busy this month."
今月は仕事がとても忙しいです。
→ polite: "Work is very busy this month."

With い-adjectives (like 忙しい, 高い, おいしい), you don’t need だ in polite form; you use the adjective + です.

Can I change the word order? For example: 仕事が今月とても忙しいです?

Japanese word order is flexible, but some orders are much more natural.

The original:

今月は仕事がとても忙しいです。
(Topic) (Subject) (Adverb) (Adjective + です)

More or less natural variants:

今月はとても仕事が忙しいです。
(Emphasis slightly shifts to "very busy work this month")
仕事が今月はとても忙しいです。
(Now "work" feels like the topic; sounds a bit marked/emphasized.)

But:

仕事が今月とても忙しいです。
is not wrong, but sounds slightly awkward because 今月 loses its clear role as topic; listeners have to work a bit harder to parse it.

The safest, most natural version is the original:
今月は仕事がとても忙しいです。

How would I say "I am very busy this month" without specifying work?

You can just remove 仕事 and keep the rest:

今月はとても忙しいです。
= "I am very busy this month."

Here, it’s understood that you are busy in general (with life, work, school, etc., depending on context).

If you want to say "I’m very busy with work this month" more directly, you can say:

今月は仕事でとても忙しいです。
- 仕事で = "because of work / with work"
  This stresses that the reason for your busyness is your job.

What’s the difference between 今月は仕事が忙しいです and 今月の仕事は忙しいです?

Subtle but important nuance:

今月は仕事が忙しいです。
- Topic: 今月 (this month, as a time frame)
- Comment: work is busy
- Natural translation: "Work is busy this month."
  Focus: This month is a busy period (because work is busy).
今月の仕事は忙しいです。
- 今月の仕事 = "this month’s work" (the work belonging to this month)
- Topic: 今月の仕事
- Natural translation: "This month’s work is busy / demanding."
  Focus: The type or content of work this month is busy/demanding.

In everyday speech, people more often say 今月は仕事が忙しいです, treating "this month" as the time frame.

How do I make this sentence negative or past tense?

The key is to conjugate the い-adjective 忙しい.

Present negative – "not busy":
- 忙しくないです (polite)
- 今月は仕事がとても忙しくないです。
  = "Work is not very busy this month." (a bit odd with とても; more natural without it)
- Better: 今月は仕事があまり忙しくないです。
  = "Work is not very busy this month." (あまり + negative)
Past tense – "was busy":
- 忙しかったです
- 先月は仕事がとても忙しかったです。
  = "Work was very busy last month."
Past negative – "was not busy":
- 忙しくなかったです
- 先月は仕事があまり忙しくなかったです。
  = "Work was not very busy last month."

Base pattern for 忙しい:

Busy (present): 忙しいです
Not busy (present): 忙しくないです
Was busy (past): 忙しかったです
Was not busy (past): 忙しくなかったです

What are the readings of the kanji in this sentence?

Readings:

今月 → こんげつ ("this month")
仕事 → しごと ("work, job")
とても → とても (all in hiragana)
忙しい → いそがしい ("busy")
です → です (copula, polite ending)

So the whole sentence is read:

こんげつはしごとがとてもいそがしいです。

Why are there spaces between the words? Japanese usually doesn’t use spaces, right?

Correct—standard Japanese writing does not use spaces between words.

The version with spaces:

今月　は　仕事　が　とても　忙しい　です。

is often used in textbooks and teaching materials to:

show you where word boundaries are,
help you see which parts are particles (は, が) and which are content words (今月, 仕事, 忙しい).

In normal Japanese text (books, websites, etc.), it would appear as:

今月は仕事がとても忙しいです。

Can I drop some particles and still be understood, like 今月仕事とても忙しいです?

In very casual spoken Japanese, some particles can be omitted, especially は and が, but you must be careful.

今月仕事とても忙しいです。
A native might understand this in conversation, but it sounds unnatural and a bit broken, especially with polite です at the end. It feels like trying to be casual and polite at the same time.

More realistic casual reductions:

Polite but a bit shortened:
- 今月、仕事がとても忙しいです。 (drop は but keep a pause/comma)
Casual speech (no です):
- 今月、仕事がめっちゃ忙しい。
- 今月、仕事すごく忙しい。 (dropping が is possible in casual talk)

For learners, it’s safest to keep the particles:

今月は仕事がとても忙しいです。

How would I say "I have a very busy job" as opposed to "Work is very busy this month"?

You’d change the structure so that 仕事 is described as a busy job, not as something that is currently busy in time.

To say "I have a very busy job":

私はとても忙しい仕事をしています。
- Literally: "I am doing a very busy job."
Or more simply:
- とても忙しい仕事です。
  (If context is clear that you’re talking about your job.)

Your original sentence:

今月は仕事がとても忙しいです。
= "Work is very busy this month." (focus on this month’s workload, not the general nature of the job)