Learn Hardcore Dutch: Wij zitten achterin de bus zodat we rustig kunnen praten. - We sit in the back of the bus so that we can talk calmly.

wij is the stressed form – you use it when you want to emphasize we (as opposed to someone else).
we is the unstressed form – it’s the one you hear most in normal speech.

In your sentence:

Wij zitten achterin de bus – starting with wij can sound a bit more emphatic: We (not others) sit at the back of the bus.
zodat we rustig kunnen praten – here we is not emphasized, so the unstressed form is natural.

You could also say We zitten achterin de bus…; that would probably be the most neutral everyday version.

Why is zitten used instead of zijn? In English we say “We are at the back of the bus”.

Dutch often uses posture verbs instead of zijn (“to be”) when talking about where people or objects are:

zitten – to sit / to be (in a sitting position)
staan – to stand / to be (upright)
liggen – to lie / to be lying
lopen – to walk / to be walking
hangen – to hang / to be hanging

So:

Wij zitten achterin de bus literally: We sit at the back of the bus, but it really means We are sitting at the back of the bus.

Using Wij zijn achterin de bus would sound odd here. For people on seats in a bus, zitten is the natural choice.

Does wij zitten mean “we sit” or “we are sitting”? There’s no continuous form in Dutch, right?

Correct: Dutch does not normally have a separate continuous form like English.

Wij zitten achterin de bus can usually be understood as:

“We are sitting at the back of the bus (right now).”

Context tells you whether it’s:

a general habit (We usually sit at the back) or
a current action (We’re sitting at the back right now).

So the simple present zitten covers both sit and are sitting.

What exactly does achterin mean here? Is it one word or two?

In this sentence, achterin is written as one word and means roughly:

“in the back (part)” / “at the back (inside something)”

So:

achterin de bus = at the back (inside) the bus

Compare:

achter in de bus – written as two words, but the meaning is very similar in practice. In speech you wouldn’t hear a difference.
Over time, achterin de bus has become a common, fixed phrase, so it’s usually written as one word.

What is the difference between achterin, achteraan, and achter?

They all involve the idea of “back/behind”, but with different nuances:

achterin de bus
= at the back inside the bus (in the back section where the seats are)
achteraan in de bus
= at the very back end of the bus (often the last rows or last spot in a line)
achter de bus
= behind the bus (outside, physically behind the vehicle)

So your sentence clearly means inside the bus, in the back area.

Why is it achterin de bus and not in de achterste van de bus or something similar?

Dutch prefers short, fixed prepositional phrases for this:

voorin de bus – at the front of the bus
midden in de bus – in the middle of the bus
achterin de bus – at the back of the bus

You could construct something like in het achterste deel van de bus, but that sounds much more formal and unnatural for everyday speech. Achterin de bus is the idiomatic, normal way to say it.

Why is the second part zodat we rustig kunnen praten and not something like … zodat we kunnen rustig praten?

Because zodat introduces a subordinate clause, and in Dutch:

in a main clause, the finite verb is in second position:
- We kunnen rustig praten.
in a subordinate clause, the verb(s) go to the end:
- … zodat we rustig kunnen praten.

Word order:

zodat (subordinating conjunction)
we (subject)
rustig (adverb)
kunnen praten (verbs at the end: modal + infinitive)

So zodat we rustig kunnen praten is correct;
*zodat we kunnen rustig praten is wrong in standard Dutch.

Can I say zodat kunnen we rustig praten like in English “so that we can talk quietly”?

No. In Dutch you cannot use main-clause (V2) word order after zodat.

Correct:

We zitten achterin de bus, zodat we rustig kunnen praten.

Incorrect:

*We zitten achterin de bus, zodat kunnen we rustig praten.

Once you use zodat, it forces subordinate-clause word order: the finite verb (here kunnen) must go to the end of that clause.

What does zodat add here? Is it purpose or result?

zodat can express both purpose (so that, in order that) and result (with the result that). Context decides.

Here:

Wij zitten achterin de bus zodat we rustig kunnen praten.

This is most naturally read as purpose:

We sit at the back of the bus *so that we can talk quietly (on purpose).*

If you wanted a “pure purpose” construction, you could also say:

We zitten achterin de bus om rustig te kunnen praten.

That’s closer to “in order to talk quietly”. Both are fine; zodat feels a bit more like linking two full sentences (cause → effect).

Why is rustig used instead of a word that literally means “quiet” or “softly”?

rustig is a flexible word meaning “calm(ly), peaceful(ly), quiet(ly)”. In this sentence:

rustig kunnen praten = to be able to talk in peace / without disturbance / calmly / quietly

Other options and nuances:

stil zijn – to be silent / to be quiet (not speaking)
- stil praten sounds odd; stil is more about not making noise at all.
zachtjes praten – to speak softly (low volume)

So:

rustig praten – calm, not rushed, not interrupted, not noisy
zachtjes praten – lower volume
stil zijn – not talking

Here rustig fits well: we sit at the back so our conversation can be calm and undisturbed.

Why is it kunnen praten and not just praten?

kunnen is a modal verb meaning “can / to be able to”.

praten – to talk
kunnen praten – to be able to talk / can talk

With zodat, the idea is:

… zodat we rustig kunnen praten.
= … so that we *can talk quietly.*

Without kunnen, it would sound more like:

… zodat we rustig praten.
This is grammatical but odd in meaning: so that we (do) talk quietly (as a kind of rule), not about having the possibility.

So kunnen expresses the possibility/ability created by sitting at the back.

Why is it kunnen praten and not praten kunnen at the end?

When you have two verbs at the end of a Dutch subordinate clause (a modal + infinitive), the usual modern order is:

modal + infinitive: kunnen praten, willen komen, moet leren

So:

zodat we rustig kunnen praten is the standard order.

Some Dutch dialects or more formal styles might sometimes use infinitive + modal, but in everyday standard Dutch for this sentence, kunnen praten is what you should learn and use.

Why is praten used instead of spreken?

Both mean “to speak / to talk”, but they have different typical uses:

praten
- more informal, everyday
- often about conversation
- met iemand praten – talk with someone
spreken
- a bit more formal
- used for languages or formal speaking
- Nederlands spreken – to speak Dutch
- met iemand spreken – to speak with someone (more formal / polite)

Since this is about casually talking together on a bus, praten is the most natural choice:

rustig kunnen praten = to be able to talk/chat calmly.

Could you rephrase the sentence in a couple of other natural ways in Dutch with the same idea?

Some natural variants:

We zitten achterin de bus, zodat we in alle rust kunnen praten.
(in alle rust = in complete peace/quiet)
We gaan achterin de bus zitten, zodat we rustig kunnen praten.
(emphasises the action of going there to sit)
We zitten achterin de bus om rustig te kunnen praten.
(purpose expressed with om … te)

All keep the same basic structure and meaning as your original sentence.