العالم كبير.

A common pronunciation is:

al-ʿālam kabīr

A rough guide:

• al- = the
• ʿā = a long aa sound, with the throat sound ع
• lam = like lum but clearer
• ka-bīr = ka-beer

Notes:

• ع is a sound English does not have. In careful MSA pronunciation, it comes from the throat.
• The ī in كبير is a long vowel, like ee in see.

With full case endings, it would be pronounced: al-ʿālamu kabīrun

In Arabic, present-tense sentences like this often do not use a separate word for is.

So:

• العالم كبير = The world is big

This is called a nominal sentence in Arabic. The idea of is is understood automatically in the present tense.

But in other tenses, Arabic does use extra words:

• كان العالم كبيرًا = The world was big
• سيكون العالم كبيرًا = The world will be big

Because العالم is the subject, the world, and كبير is the predicate, big.

In Arabic, when an adjective is used as the predicate in a sentence like this, it is usually indefinite:

• العالم كبير = The world is big

If both words were definite, the meaning would change:

• العالم الكبير = the big world

So:

• definite noun + indefinite adjective often means X is Y
• definite noun + definite adjective often means the Y X or the X that is Y

Yes, كبير is an adjective meaning big or large, but here it is functioning as the predicate of the sentence.

That means it is not just modifying a noun inside a noun phrase. It is saying something about the subject:

• العالم كبير = The world is big

Compare:

• العالم كبير = a full sentence
• العالم الكبير = a noun phrase, the big world

That contrast is very important in Arabic.

In fully vowelled MSA, it is:

العالمُ كبيرٌ

The endings are:

• العالمُ with ـُ because it is the subject of a nominal sentence
• كبيرٌ with ـٌ because it is the predicate and also nominative

In normal writing, these short vowel endings are usually omitted, so you typically see:

العالم كبير

Both forms are correct; the second is just the usual spelling in everyday texts.

Yes. Without short vowels, العالم can be read in more than one way.

Two common possibilities are:

• العالَم = the world
• العالِم = the scientist or the scholar

They are spelled the same in ordinary Arabic writing, but the vowels are different.

In your sentence, the intended meaning is the world:

• العالَم كبير = The world is big

If it meant the scientist, then:

• العالِم كبير could mean something like The scholar is great/important/elderly, depending on context

So context usually tells you which meaning is meant.

Because العالم is a masculine noun in Arabic.

Even though world is not biologically male, Arabic nouns still have grammatical gender. عالَم is grammatically masculine, so the predicate adjective appears in the masculine singular form:

• العالم كبير

If the noun were feminine, the adjective would normally also be feminine:

• المدينة كبيرة = The city is big

So this is an example of normal gender agreement.

The normal, neutral order is:

العالم كبير

This starts with the subject and then gives information about it.

You may sometimes see the predicate come first in more literary or stylistically marked Arabic, but for a learner, the standard pattern to use is:

• subject + predicate
• العالم كبير

So yes, Arabic can sometimes vary word order for emphasis or style, but this sentence in its usual form is the best model to learn first.

You would make it an ordinary noun + adjective phrase, and both words would be indefinite:

• عالَم كبير = a big world

Compare the three patterns:

• عالَم كبير = a big world
• العالم الكبير = the big world
• العالم كبير = The world is big

These three are very useful to compare, because they show how Arabic uses definiteness to signal different meanings.

Not always. كبير can mean:

• big
• large
• great
• important
• sometimes old/elder depending on context

In this sentence, with العالم, the natural meaning is big/large:

• العالم كبير = The world is big

But in other sentences, context may shift the meaning:

• هو رجل كبير can mean He is an old man or He is an important man, depending on context

So the core idea is greatness or largeness, and context decides the best English translation.