Learn Hardcore Hungarian: A főnök ma későn érkezik az irodába, de a munka már reggel elkezdődik. - Today the boss arrives late at the office, but work already starts in the morning.

You can say későn ma érkezik, but it is unusual and would sound marked or poetic at best. In everyday speech, you would keep ma (time) before későn (manner).

Common, natural alternatives:

Ma későn jön a főnök.
Ma érkezik későn a főnök. (focus on late)

Why is érkezik used instead of jön? What is the difference?

Both mean to come/arrive, but there is a nuance:

jön – to come (more general, informal, everyday)
érkezik – to arrive (more formal, emphasizes arrival at a place)

In an office or work-related context, érkezik sounds a bit more formal or neutral, like English arrive:

Ma későn jön a főnök. – The boss is coming late today. (more colloquial)
Ma későn érkezik a főnök az irodába. – The boss arrives late at the office today. (a bit more formal/neutral)

The English version uses a future meaning. Why is Hungarian using present tense (érkezik, elkezdődik) instead of a future form?

Hungarian often uses the present tense for future events when the time is clear from the context (for example, from ma, holnap, jövő héten, etc.).

So:

A főnök ma későn érkezik.
literally: The boss arrives late today.
meaning: The boss will arrive late today.

You could use explicit future (fog érkezni), but it often sounds heavier or more emphatic:

A főnök ma későn fog érkezni. – The boss will arrive late today. (stronger emphasis, maybe stressing the plan or inevitability)

In neutral speech, the simple present is very common for scheduled or clearly future events.

Why is it az irodába and not az irodában?

The endings -ba / -be and -ban / -ben express different things:

-ba / -be – into something, movement toward the inside (illative)
-ban / -ben – in / inside something, static location (inessive)

Here we have motion:

érkezik az irodába – arrives to / into the office

If you said:

érkezik az irodában – arrives in the office

this would sound odd, as if he somehow arrives while already being inside. For going to the office, you need -ba:

megyek az iskolába – I go to school
érkezik a városba – arrives in(to) the city
érkezik az irodába – arrives at the office

Why does iroda take the ending -ba and not -be?

The choice between -ba and -be follows vowel harmony:

Back vowels (a, á, o, ó, u, ú) → -ba
Front vowels (e, é, i, í, ö, ő, ü, ű) → -be

Iroda has the back vowels o and a, so it takes -ba:

irodába – into the office
iskolába – into the school
Compare with a front-vowel word:
székbe – into the chair
kertbe – into the garden

Why is there an article before irodába (az irodába) instead of just irodába?

Hungarian often uses the definite article a / az before specific places, similar to English the:

az irodába – to the office (specific office, known from context)

Without the article, irodába would sound more generic, like to an office, and in many contexts it just sounds incomplete or unnatural.

Compare:

Megyek az iskolába. – I’m going to school / the school.
Megyek iskolába. – I’m going to school. (more like the activity of schooling; possible, but a bit different)

Here, you clearly mean the boss’s specific office, so az irodába is natural.

Why is it de, and not hanem, before a munka?

Both de and hanem can be translated as but, but they are used differently:

de – general contrast (but)
hanem – but rather, used after a negation to correct something

Since the first clause is not negative, you must use de:

A főnök ma későn érkezik az irodába, de a munka már reggel elkezdődik.

Examples with hanem:

Nem este, hanem reggel kezdődik a munka.
Not in the evening, but rather in the morning the work starts.

What exactly does már mean here, and why is it before reggel?

Már usually means already. In this sentence:

a munka már reggel elkezdődik
– the work already begins in the morning

The usual neutral order is:

subject → már → time → verb

So:

A munka már reggel elkezdődik.

You can move már for emphasis:

Már reggel elkezdődik a munka. – Emphasis on already in the morning.
Reggel már elkezdődik a munka. – Emphasis on in the morning with a hint of already.

All are grammatical; the given sentence is a common, neutral pattern.

Why is reggel used by itself? Why not something like a reggel or reggelben?

Reggel is often used as an adverb meaning in the morning, so you don’t need a preposition or a case ending:

Reggel kezdek dolgozni. – I start working in the morning.
Már reggel hideg van. – It is already cold in the morning.

You can use a reggel (the morning) as a noun in other structures:

A reggel szép volt. – The morning was beautiful.

But when you are just talking about when something happens, bare reggel as an adverb is normal and idiomatic. Reggelben is not used with this meaning.

What is the difference between kezd, kezdődik, and elkezdődik?

All are related to starting / beginning, but differ in grammar and nuance:

kezd – transitive verb, someone starts something
- Elkezdem a munkát. – I start the work.
- A főnök kezdi a megbeszélést. – The boss starts the meeting.
kezdődik – intransitive, something starts (by itself)
- A film kezdődik. – The film is starting.
- A munka reggel kezdődik. – The work starts in the morning.
elkezdődik – kezdődik
- prefix el-; often gives a sense of actually starting / getting underway
- A munka már reggel elkezdődik. – The work already begins in the morning.
  (slightly stronger or more complete feeling than kezdődik)

In many contexts kezdődik and elkezdődik can be swapped without a big change in meaning; el- makes it a bit more dynamic or emphatic.

Why is it a munka már reggel elkezdődik and not Már reggel a munka elkezdődik or Elkezdődik már reggel a munka?

All of these are grammatical, but Hungarian word order encodes topic and focus:

A munka már reggel elkezdődik.
– Neutral: The topic is a munka (the work). We are telling something about it: it starts already in the morning.
Már reggel elkezdődik a munka.
– Focus on már reggel (already in the morning). Emphasizes when it starts.
Elkezdődik már reggel a munka.
– More marked, often used when stressing the action elkezdődik and adding már reggel as an emotionally colored detail (e.g. complaining).

In the original sentence, the contrast is between the boss and the work, so putting a munka at the start of the second clause nicely mirrors A főnök in the first clause:

A főnök ma későn érkezik..., de a munka már reggel elkezdődik.

Why is there a comma before de?

In Hungarian, when de connects two full clauses (each with its own subject and verb), we normally use a comma:

A főnök ma későn érkezik az irodába, de a munka már reggel elkezdődik.
[clause 1] , de [clause 2]

Both parts are complete sentences:

A főnök ma későn érkezik az irodába.
A munka már reggel elkezdődik.

So you separate them with a comma when joined by de.

Could you say Ma későn jön a főnök az irodába, de a munka már reggel kezdődik instead? Would it be wrong?

That version is perfectly grammatical, just slightly different in style and nuance:

érkezik → jön: more colloquial, less formal
elkezdődik → kezdődik: a bit less emphatic, more neutral

So:

Ma későn jön a főnök az irodába, de a munka már reggel kezdődik.

means essentially the same thing in everyday language. The original sentence is just a bit more formal or “textbook-like” with érkezik and elkezdődik.