De olifant is groot.

Because olifant is a de-word in Dutch. Dutch nouns have grammatical gender/class, and singular nouns usually take either de or het.

• de olifant = the elephant
• not het olifant

Unfortunately, whether a noun is a de-word or het-word often has to be learned with the noun itself.

It can do either, depending on context.

• It can refer to a specific elephant: The elephant is big.
• It can also be used generically: The elephant is a big animal / elephants are big type meaning.

In simple learning examples, it is often just understood as a specific elephant unless context suggests a general statement.

Because after is, the adjective is used without the extra -e ending.

Here, groot is a predicate adjective: it comes after the verb is and describes the subject.

• De olifant is groot. = The elephant is big.

But before a noun, Dutch usually adds -e:

• de grote olifant = the big elephant

So:

• after is → groot
• before olifant → grote

Yes. This sentence follows the basic Dutch main-clause order:

subject + verb + adjective

• De olifant = subject
• is = verb
• groot = adjective/complement

So it works very much like English The elephant is big.

Yes, very similarly. Is is the third-person singular form of zijn (to be).

Examples:

• Ik ben = I am
• jij bent = you are
• hij/zij/het is = he/she/it is

So in De olifant is groot, is means is.

A rough pronunciation is like khroht, but that is only approximate.

A few important points:

• g in standard Dutch is usually a harsh throat sound, not the English g in go
• oo is a long vowel, somewhat like the vowel in English boat, but not exactly the same
• t is pronounced clearly at the end

If you are learning pronunciation, the hardest part is usually the Dutch g.

Roughly: oh-li-fahnt.

Helpful notes:

• o is short and clear
• stress is usually on the last syllable: olifant
• the final t is pronounced

So the rhythm is approximately o-li-FANT.

Yes. That means An elephant is big or An elephant is large.

The difference is:

• De olifant is groot = the elephant is big
• Een olifant is groot = an elephant is big

So the article changes the meaning just as in English.

A simple rule is:

• groot when the adjective stands alone after a verb
• grote when the adjective comes before a noun

Examples:

• De olifant is groot. = The elephant is big.
• De grote olifant = The big elephant.

This is one of the most common adjective patterns in Dutch.

In normal main clauses, yes: Dutch usually follows the verb-second rule.

In this sentence:

• first element: De olifant
• second element: is

So the sentence is perfectly normal Dutch word order.

For example, if you begin with another element, the verb still usually stays second:

• Vandaag is de olifant groot.

That is a very important Dutch pattern to get used to.

Because common nouns in Dutch are not capitalized.

So:

• de olifant = correct
• de Olifant = not correct, unless it is part of a name

Dutch capitalization is closer to English than to German in this respect.

Yes. In many everyday contexts, groot can be translated as either big or large.

• De olifant is groot. = The elephant is big / large.

Which English translation sounds best depends on style and context, but big is usually the most natural basic translation.

The plural is:

De olifanten zijn groot. = The elephants are big.

Changes:

• olifant → olifanten
• is → zijn

The adjective stays groot after the verb, even in the plural.