Geraham itu besar.

It breaks down like this:

• geraham itu = the subject noun phrase
• besar = the predicate adjective

So the sentence pattern is:

[noun phrase] + [adjective]

In other words, Indonesian is saying something like:

• the/that molar
  • big

A full present-tense is is usually not needed.

Because Indonesian often omits the copula in simple present-tense sentences.

In English, you must say:

• The molar is big.

In Indonesian, it is normal to say:

• Geraham itu besar.

This is one of the most common patterns in Indonesian:

• Rumah itu besar. = The house is big.
• Anak itu pintar. = The child is smart.

So the lack of is is completely normal.

Itu literally often means that, but when it comes after a noun, it very often works like that or the, depending on context.

So geraham itu can mean:

• that molar
• the molar

This does not always sound as strongly demonstrative as English that. In many cases, it simply marks the noun as something specific or already known in the conversation.

Compare:

• geraham = molar / a molar / molars
• geraham itu = that molar / the molar

Because in this sentence, besar is not directly inside the noun phrase as a big molar. It is the predicate of the sentence: it tells you something about geraham itu.

So the sentence is structured as:

• Geraham itu = subject
• besar = what is being said about it

More broadly, Indonesian adjectives often appear after nouns, and predicate adjectives also come after the subject.

So Geraham itu besar is the natural order.

By itself, Indonesian nouns usually do not show singular vs. plural the way English does.

So geraham can mean:

• molar
• molars

and geraham itu can mean:

• that molar / the molar
• in some contexts, those molars / the molars

Usually, context tells you which one is meant.

If a speaker wants to make plural clearer, Indonesian may use reduplication:

• geraham-geraham itu = those molars / the molars

But in a simple sentence like Geraham itu besar, many learners will naturally understand it as singular unless the context suggests otherwise.

No, that would sound unnatural.

In Indonesian, adalah is usually not used before an adjective like besar.

So this is natural:

• Geraham itu besar.

But this is not the usual pattern:

• Geraham itu adalah besar. ✗

Adalah is more commonly used in formal language when the predicate is a noun phrase, not an adjective. For example:

• Geraham itu adalah gigi geraham terakhir.

For adjectives, just use the adjective directly.

A simple approximate pronunciation is:

• guh-RA-ham

A bit more precisely:

• the first e in ge- is often like the a in sofa
• r is usually tapped or lightly rolled
• the h is pronounced
• the final a is clearly sounded, not reduced away

So the whole sentence is roughly:

• guh-RA-ham EE-too buh-SAR

Also, Indonesian spelling is fairly regular, so most letters are pronounced.

Yes.

• Geraham ini besar. = This molar is big.
• Geraham itu besar. = That molar / the molar is big.

So ini and itu are a useful pair:

• ini = this
• itu = that

When they follow a noun, they point to something specific:

• buku ini = this book
• buku itu = that book

Not if you want to keep the same meaning.

• Geraham itu besar = The/that molar is big.

If you say Itu geraham besar, it no longer clearly means the same thing. It could sound more like:

• That is a big molar
• or part of a different structure

So for the meaning of your sentence, keep:

• Geraham itu besar

The noun phrase geraham itu stays together, and besar comes after it.

Yes. Besar is the normal standard word for big/large in Indonesian.

So saying a tooth, molar, house, or animal is besar is completely natural.

Some examples:

• Giginya besar. = His/her tooth is big.
• Rumah itu besar. = The house is big.

In casual speech, you may also hear gede, which also means big, but besar is the standard and safer choice for learners.