Quick facts

  • Speakers (2025)
    • 75 million as first language
    • 195 million as second language
    • 270 million speakers
  • Language family
    • Austronesian > Malayo-Polynesian > Malay-Chamic > Malayic > Malay > Bahasa Indonesia
  • Writing system
    • Latin

WORK IN PROGRESS

With more than 700 hundreds living languages, Indonesia ranks second[1] on the list of countries by most living languages. Among this impressive list, with more than 270 million speakers, resides the tenth[2] most spoken language in the world: Bahasa Indonesian, the lingua franca (common language) of the country.

Bahasa Indonesia (bahasa meaning language), was declared the official language of Indonesia in 1945, as the country declared its independence. It belongs to the Austronesian language family, and is a standardized version of Malay. Though, mutually intelligible, there are noticeable differences between Bahasa Indonesia and standardized Malay as spoken in Malaysia such as spelling, grammar, pronunciation and vocabulary, and the predominant source of loanwords [3].

Map of Austronesian languages, from Encyclopædia Britannica.
Map of Austronesian languages, from Encyclopædia Britannica.

Studying it, you’ll notice typical patterns of its family, like a generally small number of phonemes (consonant and vowel sounds), and the extensive use of affixes and reduplication.

What follows if of course not complete, as I am writing while learning. You are most welcome to clarify or correct me, in the comments 🙂

Phonology and writing system

Bahasa Indonesia uses the Latin alphabet, with a pronunciation similar to French or Italian. Most letters have only one pronunciation, making spelling straightforward. Its biggest difficulty is guessing when to pronounce ‘e’ /e/ or /ə/ (more on that just below).

Phonology wise, the language has six vowels and twenty-four total consonant, with some only used in loan-words. Let’s have a closer look at the vowels.

  • a (IPA /a/) as in “alphabet” 
  • é (IPA /e/) as in the first ‘e’ of “welcome”
  • o (IPA /o/) as in “auto” 
  • e (IPA /ə/) as in the first ‘i’ of “divide”
  • i (IPA /i/ as in the first ‘i’ of “vision”
  • u (IPA /u/) as in “blue”

In practice, ‘é’ is rarely written with its diacritic, thus guessing when to utter /e/ or /ə/ is non-trivial. Fortunately, /e/ is rather rare, making /ə/ the safest bet. In doubt, don’t hesitate using Google Translate spelling function or, even better, asking a local.

The language also has four diphthongs.

  • ai (IPA /ai/)
  • au (IPA /au/)
  • oi (IPA /oi/)
  • éi (IPA /ei/)

Of the twenty-four consonants, five are only used for loan words.

  • f (IPA /f/)
  • v (IPA /v/)
  • z (IPA /z/)
  • sy (IPA /ʃ/) as the “sh” in “sheep”.
  • kh (IPA /x/) as the “ch” in “loch“

Usually, people will pronounce ‘v’ as an /f/ as it is mainly used for Dutch loan words. Most of the remaining consonants are pronounced exactly as in English. Including some of the above. These are ‘b’, ‘d’, ‘f’, ‘g’, ‘h’, ‘j’, ‘k’, ‘l’, ‘m’, ‘n’, ‘p’, ‘s’, ‘t’, ‘w’, ‘y’, and ‘z’.

The remaining two consonants have different pronunciation.

  • c (IPA /t͡ʃ/) as a softer version of the “ch” of “chess”. 
  • r (IPA /r/) is thrilled, as you’d hear in the Spanish “perro”.

Finally, some sounds come with special rules.

  • ny (IPA /ɲ/) is pronounced like in the Spanish ‘ñ’.
  • -k at the end of a word is pronounced as a glottal stop (IPA /ʔ/).
  • -t at the end of a word is unaspirated, thus barely hearable.

Morphology and syntax

Quick summary

Bahasa Indonesia has a simple and elegant grammar. It is an agglutinative language with a productive usage of affixes. Both prefixes and suffixes operate to alter the meaning of a word. The word order is generally subject-verb-object (SVO), but can be quite liberal, even so there are neither grammatical case markers nor grammatical genders.
Its conjugation is akin to other Asian languages, such as Vietnamese or Thai. The verbs don’t inflect, and the conjugation is marked by the pronouns and auxiliary words (time adverbs), indicating if the action is happening right now, in the future, the past, or even hasn’t happened yet.

Word order and modifiers

Word order is subject-verb-object, but unlike English, the noun-modifiers (e.g. adjectives) are placed on the right of the noun. Giving a few examples:

  •  The big red cat -> Kucing (cat) merah (red) besar (big)
  • The small and green island -> Pulau (island) kecil (small) dan (and) hijau (green)

As you certainly have noticed, there is no determiner in Indonesian, and expressing specificity is done using either numeral quantifiers or demonstrative determiners (“this”, “that”). The demonstrative determiners are:

  • ini (this, these)
    • Kucing ini lucu. (This/the cat is funny.)
  • itu (that, those)
    • Buku-buku itu membosankan. (those books are boring.)

In contrast, numeral quantifiers (counters) can be used to talk about indefinite.

  • orang: people counter
    • Saya pergi bersama tiga orang kawan saya. (I went with two of my friends.)
  • ekor: animal counter
    • Ini seekor kucing. (This is a cat.)
    • Dia melihat dua ekor anjing. (She saw two cats)
  • helai: thin things counter
    • Di buku ini ada tujuh ratus helai halaman. (In this book, there are seven hundred pages.)

Using numeral quantifiers or counters is a common mechanism in other Asian languages like Chinese and Japanese. These two have around five hundred and two hundred respectively (though most are rarely used), while Indonesian has less than twenty.

Agglutinative morphology

The two biggest features of the language are agglutination by affixes and reduplication.

All types of affixes are used:

  • Prefixes, at the beginning of the word.
  • Suffixes, at the end of the word.
  • Interfixes, within the word.
  • Circumfixes, at both the beginning and the end of the word.

These affixes are added to a root word, altering or clarifying its meaning.

  1. Take a root word: tunggu (wait).
  2. Add the desired affix, for example meN- which marks a transitive verb (a verb with an object).
  3. You get menunggu (to wait for someone or something).

You probably noticed that the root word changed, it’s because some affixes slightly alter the root. But these alterations are pretty systematic and only affect a few affixes. In the case of meN-, when connected to a root starting with a vowel, it becomes meng-.

  • ajar (teach/learn/study)
  • + meN-
  • = mengajar (to teach something)


Saya mengajar Bahasa Indonesia (I teach the Indonesian language). 

The notation of a capital N to mark the flowing consonant is coming from one of my main reference on the language[4]: Indonesian for Beginners.

Let’s see a few other affixes.

Reduplication

Note

  1. List of countries by number of languages (Wikipedia, 2019)
  2. List of languages by total number of speakers (Ethnologue, 2025)
  3. Comparison of Indonesian and Standard Malay (Wikipedia)
  4. Indonesian for Beginners (Tuttle Publishing, 2025).