memper-...-i: Formation and Allomorphy | Indonesian Grammar

The template memper- + base + -i appears in important verbs such as memperbaiki “repair/improve,” memperlengkapi “equip,” and mempersenjatai “arm.” It is much more lexically restricted than its regular-looking spelling suggests. This page covers formation; meaning and the separate usage page handle semantic and syntactic choices.

The canonical structure

For spelling, the practical template is:

memper- + base + -i → memperbasei

For voice and derivational analysis, separate the active layer from the inner stem:

meN- + [per- + base + -i] → active verb

That structure explains why the active memperbaiki corresponds to passive diperbaiki and bare perbaiki, rather than to dimemperbaiki or memperbaik.

Function	Bracketing	Surface form
active	[meN-[per-[baik]-i]]	memperbaiki
di-passive	[di-[per-[baik]-i]]	diperbaiki
bare stem	[per-[baik]-i]	perbaiki

Teknisi memperbaiki mesin kopi pagi ini.

The technician repairs the coffee machine this morning.

Mesin kopi sedang diperbaiki oleh teknisi.

The coffee machine is being repaired by a technician.

Mesin kopi itu sudah kami perbaiki.

We have repaired that coffee machine.

Perbaiki alamat pengiriman sebelum membayar.

Correct the delivery address before paying.

The three forms differ in voice and clause organization, not in tense. Aspect words such as sedang and sudah locate the event in time.

💡

Compare memperbaiki, diperbaiki, and perbaiki. The stable portion perbaiki is the inner derived stem; only the outer voice marking changes.

Required segmentation table

The five rows include the three required families and two additional established formations.

Base	Analysis	Surface word	Core lexical gloss
baik	[meN-[per-[baik]-i]]	memperbaiki	repair; improve; correct
lengkap	[meN-[per-[lengkap]-i]]	memperlengkapi	equip; furnish
senjata	[meN-[per-[senjata]-i]]	mempersenjatai	arm; equip
baru	[meN-[per-[baru]-i]]	memperbarui	renew; update
ingat	[meN-[per-[ingat]-i]]	memperingati	commemorate; observe

Kami memperbaiki jadwal setelah dua pembicara membatalkan kehadiran.

We revise the schedule after two speakers cancel.

Klinik memperlengkapi ruang pemeriksaan dengan alat baru.

The clinic equips the examination room with new instruments.

Negara itu mempersenjatai pasukan penjaga pantai.

That country arms its coast guard.

Saya harus memperbarui paspor sebelum bulan depan.

I have to renew my passport before next month.

Warga memperingati Hari Kemerdekaan dengan upacara sederhana.

Residents commemorate Independence Day with a simple ceremony.

These are actual lexical items, not freely generated examples. In particular, memperbaiki is the established form; memperbaikkan is not a spelling variant.

Root consonants after the inner per-

The specialized active sequence memper- contains an inner per- boundary. Because meN- does not attach directly to the lexical base, the base-initial consonant normally remains. Mempersenjatai preserves the s of senjata; memperbaiki preserves b; memperlengkapi preserves l.

Compare a direct meN-...-i formation. In meN- + sakit + -i → menyakiti, root-initial s is deleted and the nasal surfaces as ny. The correct surface is menyakiti, never mensakiti. With inner per-, however, write mempersenjatai, not mempernyenjatai or memperenjatai.

Ucapan itu menyakiti perasaan banyak orang.

That remark hurts many people's feelings.

Pemerintah mempersenjatai unit tersebut dengan senjata standar.

The government arms that unit with standard weapons. (formal)

Donasi itu memperlengkapi perpustakaan desa dengan komputer.

The donation equips the village library with computers.

This contrast fulfills two opposite spelling duties: show deleted root consonants as deleted in analysis, but neither restore them in a direct meN- form nor delete them across per-.

Vowel boundaries before -i

Actual words are solid, and adjacent vowels remain visible. Senjata + -i gives senjatai, so the full verb has ...tai: mempersenjatai. Baru + -i gives barui, producing memperbarui. Daya + -i gives dayai in lexicalized memperdayai “deceive.” Standard orthography inserts no hyphen, apostrophe, y, or w.

Perusahaan memperbarui sistem pembayaran setiap tahun.

The company updates its payment system every year.

Penipu itu memperdayai korban dengan janji palsu.

The fraudster deceives the victim with false promises.

Pelatihan ini mempersenjatai peserta dengan keterampilan praktis.

This training equips participants with practical skills.

The final i of a word is not automatically the suffix. Memperinci “specify/elaborate” is built on rinci, whose final i belongs to the base; it is not evidence for a productive memper-...-i formation. Dictionary bracketing matters.

Laporan itu memperinci biaya setiap tahap proyek.

The report itemizes the cost of each project stage. (formal)

The inner per- loses its final r before an r-initial base. In rinci → memperinci, the single written r belongs to rinci, not simultaneously to two morphemes. That example lacks the suffix -i, but it demonstrates the r-related allomorphy of the same inner prefix. Do not write memperrinci.

The prefix also has reduced pe- before a base whose first syllable contains /ər/, as in neighboring kerja → mempekerjakan. There is no license to coin an unattested mempekerjai simply because its shape is imaginable.

Perusahaan mempekerjakan tenaga ahli dari luar kota.

The company employs specialists from outside the city.

The ajar family is the important exceptional pel-...-i member: ajar → pelajari → mempelajari, not memperajari. It is morphologically related to this network but must be memorized as an allomorphic lexical family.

Mahasiswa mempelajari data itu sebelum menulis laporan.

The students study the data before writing the report.

Bab terakhir belum kami pelajari.

We have not studied the final chapter yet.

Prosedur baru harus dipelajari oleh semua petugas.

The new procedure must be studied by all officers.

💡

The long label is not always visible letter for letter. The regular family has per-, r-sensitive contexts can reduce it to pe-, and ajar exceptionally uses pel-.

Root-category restrictions

Attested bases include adjectives (baik, lengkap, baru), nouns (senjata, daya), and psychological or relational roots (ingat, ajar). The template often creates a transitive verb whose object is improved, equipped, renewed, commemorated, or studied. Yet the inventory is small enough that analogy is unsafe.

Editor memperbaiki tiga kalimat yang kurang jelas.

The editor improves three unclear sentences.

Sekolah memperlengkapi laboratorium dengan alat keselamatan.

The school equips the laboratory with safety equipment.

Museum memperingati seratus tahun kelahiran pelukis itu.

The museum commemorates the centenary of that painter's birth.

Do not infer that every adjective takes memper-...-i. Standard Indonesian uses memperjelas “clarify,” memperbesar “enlarge,” and mempermudah “make easier,” without -i.

Diagram itu memperjelas hubungan antara kedua variabel.

The diagram clarifies the relationship between the two variables. (academic)

Tombol ini memperbesar gambar.

This button enlarges the image.

Dictionary exposure and competing analyses

Search for the full surface form and the base. A dictionary connects memperbaiki with baik, memperbarui with baru, and mempelajari with ajar. It may not list an independently usable perbarui in every display even though perbarui occurs as a directive or bare stem.

Perbarui aplikasi sebelum masuk kembali.

Update the application before signing in again.

Some words allow more than one historical or theoretical segmentation. For learners, the useful analysis is the one that predicts the active/passive/bare alternation and connects established relatives. It must not be turned into a license for unrestricted coinage.

Common Mistakes

Replacing -i with -kan in memperbaiki

❌ Teknisi memperbaikkan mesin yang rusak.

Incorrect in Standard Indonesian — the established verb is memperbaiki.

✅ Teknisi memperbaiki mesin yang rusak.

The technician repairs the broken machine.

Writing the abstract affix label inside the word

❌ Kami memper-baik-i jadwal perjalanan.

Incorrect spelling — hyphens belong only in morphological notation.

✅ Kami memperbaiki jadwal perjalanan.

We improve the travel schedule.

Deleting the protected s of senjata

❌ Mereka memperenjatai para penjaga.

Incorrect — the s of senjata remains after inner per-.

✅ Mereka mempersenjatai para penjaga.

They arm the guards.

Doubling the suffix after a vowel-final base

❌ Perusahaan memperbaruii sistem pembayaran.

Incorrect — baru plus -i surfaces as barui, with one suffix i.

✅ Perusahaan memperbarui sistem pembayaran.

The company updates its payment system.

Missing the exceptional ajar allomorph

❌ Kami memperajari bab terakhir malam ini.

Incorrect — the ajar family uses pel- in mempelajari.

✅ Kami mempelajari bab terakhir malam ini.

We study the final chapter tonight.

Treating every final i as a suffix

❌ Memperinci harus dianalisis sebagai memper- + rinc + -i.

Incorrect analysis — the base is rinci; its final i belongs to the base.

✅ Laporan itu memperinci semua biaya tambahan.

The report itemizes all additional costs. (formal)

Key Takeaways

The active, passive, and bare forms reveal an inner per-base-i stem: memperbaiki, diperbaiki, perbaiki.
Inner per- protects the base's first consonant from direct meN- substitution: mempersenjatai retains s.
Vowel-final bases attach directly: senjata + -i → senjatai, baru + -i → barui.
The inner prefix has r-sensitive variants, while ajar → mempelajari uses exceptional pel-.
The template is restricted; final i alone does not prove the presence of suffix -i.

Now practice Indonesian

Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.

Start learning Indonesian →