Het varken eet in de tuin.

Because varken is a het-word in Dutch. Dutch nouns take either de or het as their definite article, and this has to be learned with the noun.

So:

• het varken = the pig
• not de varken

A useful thing to remember:

• singular: het varken
• plural: de varkens

So even het-words usually become de in the plural.

Eet is the correct present-tense form for hij/zij/het and for singular nouns like het varken.

The verb is eten = to eat.

Present tense:

• ik eet = I eat
• jij eet / eet jij = you eat / do you eat
• hij eet = he eats
• zij eet = she eats
• het eet = it eats
• wij eten = we eat
• jullie eten = you eat
• zij eten = they eat

Since het varken is singular, Dutch uses eet.

Dutch and English both change the verb in the present tense, but they do it differently.

In English:

• I eat
• he eats

In Dutch:

• ik eet
• het varken eet

So Dutch does mark the verb, but not with an extra -s like English. The form eet is simply the correct Dutch present-tense form.

This is the normal word order for a simple Dutch main clause:

subject + verb + rest

So here:

• Het varken = subject
• eet = finite verb
• in de tuin = adverbial phrase of place

That gives:

Het varken eet in de tuin.

This is very similar to basic English word order: The pig eats in the garden.

Yes. Dutch often moves time or place expressions to the front for emphasis or style.

You can say:

In de tuin eet het varken.

That is still grammatical, but now Dutch uses the verb-second rule, so the finite verb eet must come right after the first element.

Compare:

• Het varken eet in de tuin.
• In de tuin eet het varken.

Both are correct. The first is the most neutral.

Because tuin is a de-word.

So:

• de tuin = the garden
• in de tuin = in the garden

You just use the article that belongs to the noun:

• in het huis
• in de tuin

The preposition in does not change whether the noun takes de or het.

In de tuin is the normal and correct expression for in the garden.

Dutch usually uses in for being inside an area or within a space:

• in de tuin = in the garden
• in het huis = in the house

Op de tuin would not normally be used here. Op usually means on or sometimes at in other contexts, but not for a normal garden in this sentence.

So for this idea, use:

in de tuin

No. Dutch, like English, can use eat without saying what is being eaten.

So:

• Het varken eet. = The pig is eating.
• Het varken eet in de tuin. = The pig is eating in the garden.

If you want to say what it is eating, you can add an object:

• Het varken eet een appel. = The pig is eating an apple.

It can mean either, depending on context.

Dutch often uses the simple present for both:

• a general fact or habit
• something happening now

So Het varken eet in de tuin can mean:

• The pig eats in the garden (habitual)
• The pig is eating in the garden (right now)

If Dutch speakers want to be extra explicit about something happening at this moment, they can sometimes use:

• Het varken is in de tuin aan het eten.

But the simple present is very common.

A rough English-friendly guide:

• varken ≈ VAR-ken

  • v in Dutch is often close to English v
  • the a is short, somewhat like the vowel in far but shorter
  • r may sound different depending on accent
  • -ken has a reduced second syllable

• tuin is trickier

  • it contains the Dutch diphthong ui, which does not have a perfect English equivalent
  • it is one syllable
  • a rough approximation is something like tow-yn or t-ow-in, but neither is exact

If pronunciation matters, ui is one of the famous difficult Dutch sounds for English speakers.

The plural would be:

De varkens eten in de tuin.

Changes:

• het varken → de varkens
• eet → eten

So:

• singular: Het varken eet in de tuin.
• plural: De varkens eten in de tuin.

Here, het is the definite article meaning the.

So:

• het varken = the pig

Dutch het can also be a pronoun meaning it, but not in this sentence.

Compare:

• Het varken eet. = The pig eats. → here het = the
• Het eet. = It eats. → here het = it

So the role of het depends on how it is used in the sentence.