For a native speaker of English, learning Indonesian is harder than learning any Romance of Germanic language. This is because English is a Germanic language which has borrowed about half of its vocabulary from Romance languages, mainly French.
But is Indonesian more difficult to learn than a Slavonic language such as Russian or Polish? I don’t think so. And it is definitely easier to learn than Arabic, Turkish, Hindi, Chinese, or Vietnamese.
Of course, when you are a speaker of a related language, such as Filipino, Malay, Malagasy, or any Polynesian language, then Indonesian is very easy to learn. This is because all these languages belong to the same family of Austronesian languages.
Consider this scenario: if you’re a native Turkish, Chinese, or Finnish speaker with no foreign language proficiency, which language is easier to learn: English or Indonesian? The unequivocal answer: Indonesian.
Simple Phonology and Orthography and no Tenses
Indonesian is much easier to learn than English, French, Hindi, or Thai. In fact, it ranks among the least challenging languages to acquire. What makes it so accessible is its straightforward pronunciation, devoid of tones or intricate phonology. While Indonesian grammar isn’t necessarily “simple,’ it’s certainly less convoluted than English grammar. English orthography is a nightmare for every learner (even for native speakers!), whereas Indonesian orthography is very straightforward as there is an almost perfect correspondence between phonemes (sounds of the language) and graphemes (letters of the alphabet).
Unless Arabic, or many Asian languages, Indonesian does not have a complicated script to learn. It uses the Roman (Latin) alphabet —the same script I am using in writing this text. The Roman alphabet was introduced by the Dutch in the 19th century and replaced a number of other alphabets that previously were used to write Malay, as the Indonesian language was then known. It was in 1928 when Malay was renamed as Indonesian and declared to become the language of a future independent Indonesia.
What makes Indonesian easy to learn is, aside from its phonological and orthographic simplicity, is its absence of verb conjugation (run, runs, running, ran), noun declension (house, houses), and articles (like der, die, das in German). Additionally, it lacks tense markers (I eat, ate, have eaten, will eat), relying instead on temporal indicators such as akan (future), sudah (past), and sedang (in progress).
Complex Morphology
On the other hand, Indonesian has a very complex morphology with prefixes, suffixes, circumfixes and infixes. From the root word tunjuk (point), several nominal and verbal forms can be formed, including menunjuk (to point), menunjuki (to provide guidance), menunjukkan (to show, point out), mempertunjukkan (to show, demonstrate, display), pertunjukan (a show, performance), petunjuk (instruction, clue, hint), penunjuk (a guide, indicator), penunjukan (appointing, assigning, nominating), ditunjuk (selected, appointed), ditunjukkan (shown, demonstrated), and telunjuk (index finger).
Indonesian also has two forms of passive voice, one with the prefix di-, and the other without any prefix:
Uang itu sudah diambil.
The money has been taken.
Uang itu sudah saya ambil.
The money has been taken by me.
While the latter construction may sound awkward in English, where active voice (I took the money) predominates, it’s commonplace in Indonesian, where passive constructions abound.
Despite these apparent linguistic complexities, the average Indonesian learner can engage in conversation with native speakers after four semesters of study, three hours per week—much faster than learners of Thai, Vietnamese, or Hindi.