Han arbejder i firmaet i byen.

In Danish, verbs do not change form depending on the subject.

• jeg arbejder – I work / I am working
• du arbejder – you work
• han/hun arbejder – he/she works
• vi arbejder – we work
• I arbejder – you (plural) work
• de arbejder – they work

So arbejder is used for all persons in the present tense. There is no -s ending like English he works.

Arbejder is the present tense.

Danish present tense usually covers both English simple present and present continuous:

• Han arbejder i firmaet i byen.
  → He works in the company in town.
  → He is working in the company in town.

Context will tell you whether it is a general fact (his job) or something happening right now.

The preposition i generally means in / inside and is used for:

• being inside a building or enclosed space:
  
  • i huset – in the house
  • i butikken – in the shop
  • i firmaet – in the company (physically in the company’s premises)
• being in a city, town, or country:
  
  • i byen – in the town / in town
  • i Danmark – in Denmark

På is often used with workplaces but in more fixed expressions, like:

• på arbejde – at work
• på kontoret – at the office
• på skolen – at the school

So i firmaet sounds like you are in the company as an organization or physically in its building. Han arbejder for firmaet would mean He works for the company (he is employed by them), focusing more on who he works for than where he is physically.

Firmaet is the definite form: the company.

• et firma – a company
• firmaet – the company

In Danish, the definite article (the) is usually added as an ending to the noun:

• en by – a town
• byen – the town
• et firma – a company
• firmaet – the company

So i firmaet means in the company, referring to a specific company you and the listener know about.

Byen is also in the definite form:

• en by – a town / a city
• byen – the town / the city

The expression i byen can mean:

1. Literally in the town/city (a specific town), or
2. More idiomatically in town / downtown (as opposed to at home or in the countryside).

So Han arbejder i firmaet i byen can be understood as:

• He works in the company that is in town, or
• He works in the company in town (in the urban area, not out in the countryside).

Context would clarify which nuance is meant.

Yes, repeating i like this is completely normal in Danish.

You can think of it as:

• i firmaet – in the company
• i byen – in the town

Stacking adverbials like that is very common:

• Han bor i huset på hjørnet. – He lives in the house on the corner.
• Hun arbejder på kontoret i centrum. – She works at the office in the center.

Each prepositional phrase adds extra information, and you keep the preposition for each one.

Han arbejder i byen i firmaet is grammatically possible, but it sounds unnatural and confusing to a native speaker.

In Danish, we usually put the more general location last:

• Han arbejder i firmaet i byen.
  → First: specific place (the company),
  → Then: broader location (in town).

Reversing them makes the sentence feel awkward and can make listeners pause to reinterpret what modifies what. The original order is much more idiomatic.

Danish has two grammatical genders: common (n-words) and neuter (t-words).

• by is a common gender noun:

  • en by – a town
  • byen – the town

• firma is a neuter gender noun:

  • et firma – a company
  • firmaet – the company

Gender affects:

• which indefinite article you use (en or et), and
• which definite ending you add (-en / -n for common, -et / -t for neuter).

Yes, you could say:

• Han arbejder for firmaet i byen.

Differences:

• i firmaet – focuses on being in the company/the company’s premises (location).
• for firmaet – focuses on working for the company (employment/representation), not necessarily inside its building.

So:

• Han arbejder i firmaet i byen.
  → He works in the company in town (he’s physically at the company).

• Han arbejder for firmaet i byen.
  → He works for the company in town (he is employed by or represents that company; he might work from home, travel, etc.).

Approximate pronunciation in simplified English terms:

• arbejder ≈ [ˈɑːbɑjɐ]

Key points:

• ar-: like “ar” in “far”, but with a more open a.
• -bej-: the ej is like “eye” in English.
• -der: the d is very soft, almost like a light “th” or sometimes nearly silent, and the -er is a weak, reduced vowel, a bit like “uh”.

So loosely: AR-bye-uh, with the stress on the first syllable.

Yes, by covers both town and city in everyday Danish.

• en by / byen – a town, a city (context decides how big you imagine it)

If you specifically want to say city, you can use:

• stor by – big city
• storby – large metropolitan city (more formal/compound)

But in normal speech, by is flexible, and i byen is often understood simply as in town / downtown rather than making a strict town–city distinction.