Learn Hardcore Dutch: Buiten de kantooruren mail ik mijn vragen, zodat hij ze later rustig kan beantwoorden. - Outside office hours I email my questions so that he can answer them calmly later.

Buiten de kantooruren mail ik mijn vragen …
1st element = Buiten de kantooruren
2nd element = mail (conjugated verb)
3rd element = ik (subject)

If you start with the subject instead, you get the neutral order:

Ik mail mijn vragen buiten de kantooruren.

Both are correct. The given sentence simply emphasizes the time frame by putting it first, which then forces mail ik because of the V2 rule.

What exactly does Buiten de kantooruren mean, and could I use na de kantooruren instead?

Buiten de kantooruren literally means outside the office hours, i.e. not during office hours. It refers to any time before or after the normal working day (and usually weekends, etc.).

Buiten de kantooruren → outside that time window (more general)
Na de kantooruren → specifically after office hours (not before)

So na de kantooruren only covers the time later in the day; it doesn’t include, for example, very early in the morning before the office opens. In most contexts here, buiten de kantooruren is the more natural phrase.

Why is it de kantooruren and not het kantooruren? And why is uren plural?

Uur (hour) is a het‑word in the singular: het uur.
But the plural is de uren.

Kantooruren is just kantoor (office) + uren (hours) as a compound, and the head of the compound is uren, which is plural and always takes de:

het uur → de uren
kantoor + uren → de kantooruren

We say kantooruren in the plural because we’re talking about a range of hours (the whole block of a working day), not a single hour.

Why is kantooruren written as one word?

Dutch tends to write compound nouns as a single word:

kantoor (office) + uren (hours) → kantooruren (office hours)
huis
- werk → huiswerk
tafel
- blad → tafelblad

So kantooruren follows the normal compounding rule. Writing it as kantoor uren would look wrong and could be confusing.

Can I also say Buiten kantooruren without de?

Yes, you can hear both:

Buiten de kantooruren
Buiten kantooruren

With de, it sounds a bit more like a specific, known set of hours (e.g. the official hours of a particular company).
Without de, it feels slightly more generic: outside office hours in general.

Both are acceptable and natural; the difference is subtle.

How is the verb mailen used? Is it informal, and are there alternatives?

Mailen is a regular, fairly informal verb derived from e‑mail:

ik mail
jij/u mailt
hij/zij mailt
wij/jullie/zij mailen
past: ik mailde, zij hebben gemaild

In writing, you’ll see:

mailen or e‑mailen → to email
een mail / een e‑mail sturen → to send an email
een bericht sturen → to send a message (more general)
iets per mail sturen → to send something by email

In semi‑formal contexts, mailen is fine, especially in business Dutch. If you want to sound a bit more formal, you might say:

Ik stuur mijn vragen per e‑mail.
Ik stuur hem mijn vragen per mail.

Why is it mijn vragen (plural) here? Could I also say mijn vraag?

Mijn vragen refers to several questions you have for this person. That’s the most natural reading in many real‑life situations.

If you truly only have one question, you can absolutely say:

Buiten de kantooruren mail ik mijn vraag, zodat hij ze later rustig kan beantwoorden.

But then you must also change ze (them) to a singular form:

… zodat hij die later rustig kan beantwoorden. (that [question])
Or: … zodat hij die later rustig kan beantwoorden.

So the plural in vragen is just reflecting that we’re talking about multiple questions.

What does zodat mean here, and how is it different from dus or om … te?

Zodat introduces a subordinate clause expressing purpose or result:

… mail ik mijn vragen, zodat hij ze later rustig kan beantwoorden.
→ I email my questions so that he can answer them later in peace.

Contrast:

dus = so, as a consequence/result in a main clause:
Hij is druk, dus ik mail mijn vragen.
He is busy, so I email my questions.
om … te = in order to
- infinitive, also purpose:
  Ik mail mijn vragen om hem tijd te geven.
  I email my questions (in order) to give him time.

Here, zodat nicely connects two full clauses and focuses on the intended effect: that he can answer later calmly.

Why is the word order hij ze later rustig kan beantwoorden in the second part? Could it be ordered differently?

Zodat introduces a subordinate clause, and in Dutch subordinate clauses the conjugated verb cluster goes to the end.

Inside that clause:

hij – subject
ze – unstressed object pronoun (them)
later – time adverb
rustig – manner adverb
kan beantwoorden – verb cluster (modal + infinitive) at the end

So:

zodat hij ze later rustig kan beantwoorden

The default order is roughly: subject → object pronouns → time → manner → place → verbs.

Alternative grammatically possible orders (like … zodat hij later ze rustig kan beantwoorden) either sound marked, clumsy, or unnatural in standard Dutch. The given order is what native speakers would normally use.

Why is it kan beantwoorden and not just beantwoordt?

Kan is the modal verb kunnen in the 3rd person singular: hij kan = he can / is able to.

… zodat hij ze later rustig kan beantwoorden.
→ … so that he can answer them later calmly / at ease.

Without kan, you say:

… zodat hij ze later rustig beantwoordt.

This is grammatically fine, but it sounds more like a simple statement of what happens, not about giving him the opportunity/possibility to do it calmly. Using kan emphasizes:

ability / possibility / having the time and space to answer.

What does rustig mean here, and is it an adjective or an adverb?

Rustig literally means calm / quiet.

In this sentence it functions as an adverb, modifying the way he answers:

… zodat hij ze later rustig kan beantwoorden.
→ so that he can answer them calmly / without being rushed.

As an adjective, you see it with a noun:

een rustige middag – a calm afternoon
een rustig persoon – a calm person

As an adverb, it often means:

without stress / without hurry / in a relaxed way:
Neem je tijd, lees het rustig door. – Take your time, read it calmly / at your leisure.

Why is it beantwoorden and not antwoorden?

Dutch has both:

(iemand) antwoorden (op iets) – to answer (someone) to (a question)
(iets) beantwoorden – to answer (a question, mail, etc.; take it as a direct object)

So you can say:

Hij antwoordt op mijn vragen. – He answers my questions.
Hij beantwoordt mijn vragen. – He answers my questions.

With vragen, beantwoorden is very common and sounds natural and slightly more formal/neutral:

vragen beantwoorden – to answer questions
mails beantwoorden – to answer emails
een verzoek beantwoorden – to respond to a request

That’s why the sentence has … zodat hij ze later rustig kan beantwoorden: ze is the direct object of beantwoorden.

Why is there a comma before zodat?

In Dutch, when a subordinate clause introduced by a conjunction like zodat, omdat, hoewel, als etc. comes after a main clause, a comma is normally written before it:

Ik werk thuis, omdat ik ziek ben.
Hij belt me, als hij klaar is.
Buiten de kantooruren mail ik mijn vragen, zodat hij ze later rustig kan beantwoorden.

The comma helps mark the boundary between the main clause and the subordinate clause. It’s standard punctuation in this position.

What does ze refer to, and why not hen or die?

In this sentence:

mijn vragen → plural, common gender
ze = unstressed pronoun for plural objects → them

So ze refers back to mijn vragen:

… zodat hij ze later rustig kan beantwoorden.
→ so that he can answer them later calmly.

Alternatives:

hen – stressed object pronoun (mainly for people; in modern Dutch, many speakers use ze instead even for people)
die – demonstrative pronoun (those); a bit more emphatic or contrastive

You could say:

… zodat hij die later rustig kan beantwoorden.

That would sound like those (in particular), with more emphasis. The neutral, everyday choice for vragen here is ze.