Air itu berasal dari sumber ini.

Yes—this is a very common beginner confusion.

In Indonesian, air means water, not air in the English sense. It is pronounced roughly like ah-eer, not like the English word air.

So:

• air = water
• English air = usually udara in Indonesian

This is just a false friend: it looks familiar to English speakers, but it means something different.

Itu usually means that.

So air itu literally means that water.

In Indonesian, demonstratives like ini (this) and itu (that) normally come after the noun:

• air ini = this water
• air itu = that water
• sumber ini = this source
• sumber itu = that source

This is different from English, where this/that come before the noun.

Because Indonesian usually places ini and itu after the noun they describe.

So the pattern is:

• noun + ini = this + noun
• noun + itu = that + noun

Examples:

• rumah ini = this house
• buku itu = that book
• sumber ini = this source

So sumber ini is completely normal Indonesian word order.

Because they refer to two different things with two different degrees of distance or focus:

• air itu = that water
• sumber ini = this source

So the speaker is contrasting them a little: the water is being treated as something already identified or more distant, while the source is something close to the speaker or currently being pointed out.

This is very natural in Indonesian. You can mix ini and itu in the same sentence if the context supports it.

Berasal dari means to come from, to originate from, or to have its source in.

In this sentence:

• Air itu berasal dari sumber ini. = That water comes from this source. = That water originates from this source.

It is commonly used for origins, sources, and places of origin:

• Dia berasal dari Jakarta. = He/She comes from Jakarta.
• Kata itu berasal dari bahasa Arab. = That word comes from Arabic.
• Air itu berasal dari mata air pegunungan. = That water comes from a mountain spring.

So berasal dari is a standard expression for origin.

Sometimes, yes, especially in casual speech, but it is less explicit.

• Air itu berasal dari sumber ini sounds clearer and more standard for saying the water originates/comes from this source.
• Air itu dari sumber ini may be understood in context, but it is more elliptical, like That water is from this source.

So for learners, berasal dari is the safer and more natural full form when talking about origin.

In berasal, the prefix ber- is part of the verb form.

Very roughly, ber- often helps form intransitive verbs in Indonesian. However, with berasal, it is best to learn the whole expression berasal dari as a chunk meaning to come from / originate from.

So instead of trying to translate it piece by piece too mechanically, it is more useful to remember:

• berasal dari = come from, originate from

That will help you use it naturally.

No separate word for is is needed here.

The sentence already has the verb berasal:

• Air itu berasal dari sumber ini.
• literally: That water originates from this source.

Indonesian often does not use a separate verb equivalent to English to be in the same way English does. In this sentence, the main verb is berasal, so there is no need for is.

The basic structure is:

• Air itu = subject
• berasal dari = verb phrase
• sumber ini = complement

So the pattern is roughly:

Subject + Verb + Prepositional/Source phrase

Breaking it down:

• Air itu = that water
• berasal dari = comes from
• sumber ini = this source

So Indonesian word order here is quite similar to English overall, except for the placement of ini/itu after the nouns.

Yes. That would also be grammatical, but the meaning changes:

• Air itu berasal dari sumber ini. = That water comes from this source.
• Air ini berasal dari sumber itu. = This water comes from that source.

So the grammar is the same; only the speaker’s point of reference changes.

Sumber generally means source.

It can be used in many contexts:

• sumber air = water source
• sumber energi = energy source
• sumber masalah = source of the problem
• sumber informasi = source of information

In your sentence, sumber is understood as the source the water comes from. Depending on context, that could mean a spring, supply point, or origin point.

If someone wants to be more specific, they might say something like:

• mata air = spring
• sumber air = water source

But sumber by itself is perfectly possible if the context is clear.

A simple learner-friendly pronunciation is:

AH-eer EE-too ber-AH-sahl DAH-ree SOOM-ber EE-nee

A few notes:

• air = ah-eer
• itu = ee-too
• ini = ee-nee
• dari = dah-ree
• sumber = soom-ber
• berasal = roughly ber-ah-sahl

Indonesian pronunciation is generally more regular than English spelling, so once you know the sounds, reading gets easier quickly.