Saudaranya lebih pesimis dan takut proyek sampingan itu akan mengganggu kuliah.

-nya is a flexible third-person marker. In Saudaranya, it most naturally means:

• his/her sibling (or relative), depending on context
• It can also sometimes mean “the sibling” when the person is already known from context.

Indonesian doesn’t mark gender in -nya, so:

• Saudaranya = his sibling / her sibling / their sibling / the sibling
  You decide which one in English based on the broader context, not from the word itself.

Saudara is a general kinship word that can mean:

• sibling (brother or sister)
• relative / family member (in some contexts)

In everyday talk, saudara + -nya like in Saudaranya most often means his/her sibling.

Note: In formal Indonesian, Saudara (capital S) is also used as a formal “you” in speeches or writing, but that is not the meaning here. Here, it’s about a family member.

Yes, lebih pesimis dan takut is natural and correct.

• lebih pesimis = more pessimistic
• takut = afraid

Both pesimis and takut function like adjectives here, describing the same person. Indonesian often does not repeat degree words like lebih if they clearly apply to both adjectives:

• lebih pesimis dan (lebih) takut
  → the second lebih is understood and can be dropped.

You could say lebih pesimis dan lebih takut, and it’s also correct, just a bit more explicit or emphatic.

In this sentence, takut is working in both ways at once, which is normal in Indonesian.

1. As an adjective:

   • lebih pesimis dan takut → more pessimistic and afraid

2. As a verb-like predicate that takes a clause:

   • takut [proyek sampingan itu akan mengganggu kuliah]
   • = is afraid (that) the side project will disturb the studies

Indonesian doesn’t always separate “verb” vs “adjective” as strictly as English does, so words like takut, marah, senang can behave as both.

Indonesian commonly omits bahwa when the meaning is clear. So:

• takut proyek sampingan itu akan mengganggu kuliah
  = afraid (that) the side project will disturb his/her studies

You could say:

• takut bahwa proyek sampingan itu akan mengganggu kuliah

This is also correct but sounds more formal or written. Everyday speech usually drops bahwa in this kind of sentence.

In Indonesian, the main noun usually comes first, and descriptors follow it:

• proyek = project (main noun)
• sampingan = side / secondary (describing the project)

So:

• proyek sampingan = side project

The order sampingan proyek is not natural here. Adjectives and many descriptive words come after the noun.

Sampingan literally relates to something “on the side”. It suggests:

• It’s not the main focus or activity.
• It’s additional or secondary.

So proyek sampingan can be understood as:

• a side project
• an extra project done alongside the main activity (like studying or a main job)

It’s close to the idea of “on the side” in English, e.g., I do this on the side.

Itu is a demonstrative that often works like:

• “that”
• or sometimes like “the” (to show that something is specific/known)

In proyek sampingan itu, it signals that:

• The side project is specific and already known to both speaker and listener.
• So: proyek sampingan itu ≈ that side project / the side project (we talked about).

Without itu:

• proyek sampingan = a side project (in general)
• proyek sampingan itu = that particular side project.

You could say proyek sampingan-nya, and it would mean:

• his/her side project

Differences:

• proyek sampingan itu

  • focuses on that specific project already known in the conversation
  • doesn’t say whose it is (though context usually implies it)

• proyek sampingan-nya

  • explicitly marks it as his/her project
  • still usually also refers to a specific project

Which one you choose depends on whether you want to emphasize the owner (his/her) or just that particular project.

Akan marks future or expected action.

• akan mengganggu = will disturb / is going to disturb

You can omit akan:

• takut proyek sampingan itu mengganggu kuliah
  → still usually understood as future in this context (because of takut and common sense).

Nuances:

• With akan:
  
  • a bit more explicit about the future
  • can sound slightly more formal or careful
• Without akan:
  
  • more neutral/natural in everyday speech
  • the time reference is deduced from context

Mengganggu is a transitive verb:

• mengganggu [object] = to disturb / to interfere with / to disrupt [object]

In the sentence:

• mengganggu kuliah
  
  • mengganggu = disturb / interfere with
  • kuliah = studies/university classes

So literally:

• disturb (his/her) studies / interfere with (his/her) college

Grammatically, kuliah is the direct object of mengganggu.

Kuliah is flexible and can mean:

• university/college studies in general
• lectures/classes at university
• the act of studying at university (“to be in college”)

In this sentence, kuliah is best understood as:

• his/her university studies
• or his/her college life/education

So mengganggu kuliah = interfere with / disturb his/her studies at university.

By itself, Saudaranya is number-neutral:

• It could be one sibling
• or multiple siblings/relatives, depending on the context.

In most everyday contexts, if nothing else suggests plural, people tend to understand Saudaranya as one sibling. To be clearer, Indonesian can add:

• Seorang saudaranya = one of his/her siblings
• Saudara-saudaranya = his/her siblings (plural).