Adik perempuan saya ingin ikut lomba menulis pada Maret tahun depan.

Adik means younger sibling. By itself, it does not tell you whether the sibling is male or female.

So adik perempuan means younger sister.

A useful comparison:

• adik perempuan = younger sister
• adik laki-laki = younger brother
• kakak perempuan = older sister
• kakak laki-laki = older brother

Because adik alone only means younger sibling. Indonesian often adds perempuan or laki-laki when the gender needs to be made clear.

So:

• adik saya = my younger sibling
• adik perempuan saya = my younger sister
• adik laki-laki saya = my younger brother

If the context already makes it obvious, speakers often just say adik saya.

In Indonesian, possession usually works as:

noun + possessor

So:

• adik perempuan saya = my younger sister
• rumah saya = my house
• teman saya = my friend

This is different from English, where the possessor usually comes first.

Yes. Adik perempuanku also means my younger sister.

The difference is mostly style and register:

• adik perempuan saya sounds more neutral or polite
• adik perempuanku sounds more personal or informal

Similarly:

• saya = I / me / my in a more neutral or polite style
• aku and -ku = more casual or intimate

Ingin means want, wish, or would like to.

In this sentence, ingin ikut means wants to join / wants to take part.

Compared with mau:

• ingin is a bit more formal or neutral
• mau is very common in everyday speech and often sounds more conversational

So both of these are possible:

• Adik perempuan saya ingin ikut lomba menulis.
• Adik perempuan saya mau ikut lomba menulis.

Both are natural.

Because Indonesian does not use a separate infinitive marker like English to.

After verbs such as ingin, mau, bisa, or suka, the next verb usually comes directly after it.

Examples:

• ingin ikut = want to join
• suka membaca = like to read
• bisa datang = can come

So ingin ikut is completely normal Indonesian.

Here, ikut means join, take part, or participate.

With events such as competitions, ikut is very common:

• ikut lomba = join a competition
• ikut ujian = take an exam
• ikut rapat = join a meeting

So ingin ikut lomba menulis means wants to take part in a writing competition.

Yes. Both are natural, but they feel slightly different.

• ikut lomba menulis = more everyday and direct
• mengikuti lomba menulis = a bit more formal or explicit

So these are both fine:

• Adik perempuan saya ingin ikut lomba menulis.
• Adik perempuan saya ingin mengikuti lomba menulis.

Lomba means competition or contest.

Menulis means to write or writing.

So lomba menulis literally means something like a writing contest or a competition in writing.

This kind of structure is common in Indonesian:

• lomba menulis = writing competition
• kelas memasak = cooking class
• kursus berenang = swimming course

The second word often names the activity.

The basic root is tulis = write.

But in normal usage, Indonesian usually uses a derived form, not the bare root, in a sentence like this.

• menulis = to write / writing as an activity
• tulisan = a piece of writing, written text, article, composition

So:

• lomba menulis = a competition in the activity of writing
• lomba tulisan would sound more like a competition involving written works or texts, not the usual way to say writing competition

That is why lomba menulis is the natural phrase here.

Pada is a preposition often used with time expressions, especially in more formal or careful Indonesian.

So pada Maret tahun depan means in March next year.

It is similar to English on / in / at, depending on context.

In everyday Indonesian, time expressions are sometimes used without pada, but pada sounds correct and clear here.

You may also hear:

• pada bulan Maret tahun depan = in the month of March next year

Yes. Maret tahun depan means March of next year, or simply next March.

The order is:

• Maret = March
• tahun depan = next year

Together, they form one time expression:

• pada Maret tahun depan = in March next year

Yes, somewhat. The basic order here is:

subject + ingin + verb phrase + time

So:

• Adik perempuan saya = subject
• ingin = wants to
• ikut lomba menulis = join the writing competition
• pada Maret tahun depan = in March next year

You can also move the time phrase to the front for emphasis:

• Pada Maret tahun depan, adik perempuan saya ingin ikut lomba menulis.

That is also natural Indonesian.