Wij bewaren een borrelhap voor het geval de catering laat is.

Both wij and we mean we.

• we is the unstressed, much more common form in everyday speech.
• wij is the stressed form.

So wij bewaren... can sound a little more emphatic, like:

• We are the ones saving it.
• We are saving it, not someone else.

In many contexts, you could also say We bewaren een borrelhap... and it would sound perfectly natural.

Bewaren means to keep, to save, or to put aside.

In this sentence, it means something like:

• to save
• to keep back
• to set aside

So the idea is that they are not eating it now; they are keeping it available for later.

A borrelhap is a small snack eaten with drinks, especially alcoholic drinks, in a social setting.

A borrel is an informal drink or drinks gathering, and a hap is literally a bite or snack. So a borrelhap is:

• a drinks snack
• a nibble
• an appetizer-type snack served with drinks

It is a compound noun:

• borrel
  • hap = borrelhap

You may also see borrelhapje, which is a very common diminutive form and sounds a bit more natural for a small snack item.

Because the sentence is talking about one snack or one snack item/portion being kept aside.

Dutch often uses the singular when referring to one item in a practical, everyday way. Depending on context, een borrelhap could mean:

• one specific snack
• one portion of snack food
• one appetizer item

If you wanted to make it explicitly plural, you could say:

• Wij bewaren wat borrelhapjes... = We’re saving some snacks...

Voor het geval means in case.

It is a fixed expression. More fully, you can also say:

• voor het geval dat

So these are possible:

• voor het geval de catering laat is
• voor het geval dat de catering laat is

Both mean in case the catering is late.

Because geval is a neuter noun in Dutch, so it takes het:

• het geval = the case

Literally, voor het geval is something like:

• for the case

But in natural English, it simply means in case.

So this is not something you usually translate word-for-word; it is better to learn voor het geval (dat) as a set phrase.

Because de catering laat is is a subordinate clause.

After expressions like voor het geval (dat), Dutch normally sends the finite verb to the end of the clause.

Main clause word order:

• De catering is laat. = The catering is late.

Subordinate clause word order:

• ... voor het geval de catering laat is. = ... in case the catering is late.

This is one of the most important Dutch word-order patterns to get used to:

• main clause: finite verb usually in second position
• subordinate clause: finite verb usually near the end

Yes. That is completely correct.

Both are natural:

• voor het geval de catering laat is
• voor het geval dat de catering laat is

The version without dat is often a bit more streamlined in everyday Dutch, but both are common.

Because catering is a de-word in Dutch:

• de catering

It refers to the catering service, the food provider, or the arranged food delivery/setup.

Even though the word looks English, it is also used as a Dutch noun, with Dutch article behavior.

Here, laat means late.

It is used with zijn:

• laat zijn = to be late

So:

• de catering laat is = the catering is late

Do not confuse this with other meanings of similar-looking words in Dutch. In this sentence, it is simply the adjective late.

Dutch often uses the present tense for things that are happening now or are relevant to a future possibility.

So:

• Wij bewaren... = We are saving/keeping...
• ... de catering laat is = ... the catering is late

Even though the situation may refer to a possible future problem, Dutch does not need a special future tense here. The present tense works naturally, just as in English:

• We’re saving a snack in case the catering is late.

Not exactly.

• als usually means if or when
• voor het geval means in case

Compare the ideas:

• als de catering laat is = if the catering is late
• voor het geval de catering laat is = in case the catering is late

Voor het geval suggests taking a precaution beforehand. That fits this sentence well: they are saving a snack as a precaution.

Yes, it is grammatical and understandable.

A few native speakers might more naturally say something like:

• Wij bewaren een hapje voor het geval de catering laat is.
• We houden een borrelhap achter voor het geval de catering laat is.
• We bewaren wat borrelhapjes voor het geval de catering laat is.

But the original sentence is still perfectly clear Dutch. The main learning points in it are very useful:

• bewaren
• borrelhap
• voor het geval (dat)
• subordinate clause word order with ... laat is