The research team, led by Prihantoro of Diponegoro University in Semarang, Indonesia, together with colleagues at Diponegoro and at Xi’an Jiaotong-Liverpool University in Suzhou, China, set out to move beyond the traditional way idioms have been catalogued. Dictionaries and folklore collections list idioms, but they say little about how frequently each one is actually used, in what contexts, or with what emotional coloring. Those questions demand data, and lots of it. The team therefore turned to corpus linguistics, the branch of language science that treats large, machine-searchable collections of real texts as the primary evidence for how a language works.

Their hunting ground was the LCC Indonesian 2023 corpus, accessed through the CQPweb query interface. This is a very large collection of Indonesian text drawn from web pages, news, and other publicly available sources, and it is big enough to reveal not just whether an expression exists but whether it lives a healthy life in ordinary usage. The researchers combined this data-driven approach with introspective methods, meaning they used their own native and expert knowledge of Indonesian to design queries, interpret matches, and classify the expressions they found. That hybrid strategy matters, because idioms are notoriously slippery for automated tools: a literal mention of a night butterfly is not the same thing as the idiom kupu-kupu malam, which literally translates as night butterfly but figuratively means a prostitute.

That last example illustrates the creative range of the Indonesian idiomatic zoo. The study highlights expressions such as cinta monyet, literally monkey love, which corresponds to English puppy love and describes the fleeting romantic attachments of adolescents. Tikus kantor, literally office rat, is the standard colloquial label for a corrupt official, evoking a rodent gnawing away at public resources from within the bureaucracy. Kupu-kupu malam, the night butterfly, belongs to a long cross-linguistic tradition in which moths and butterflies flutter around metaphorical meanings related to nightlife and sex work. Each of these expressions compresses a social judgment, a visual image, and a cultural history into a two-word phrase, which is precisely what makes idioms such a fascinating object of computational study.

Methodologically, the challenge was to build corpus queries that would capture these expressions reliably. Idioms resist simple keyword search because their component words also occur literally: rats really do appear in Indonesian texts about offices, and monkeys really do appear in stories about love. The researchers therefore had to design queries that could distinguish idiomatic from literal readings, and then apply their own judgment to validate the matches. This combination of automated retrieval and human verification is now standard best practice in corpus-based idiom research, but it is labor-intensive, and the study demonstrates how much can be learned when it is done carefully on a major language that has received less attention in this literature than English, German, or Mandarin.

The first major finding concerns frequency and idiomaticity. Most of the animal idioms the team profiled turned out to be highly idiomatic, meaning that their figurative meanings dominate and their literal readings are rare or absent in the corpus, yet their overall frequencies were only moderate. In other words, these are established expressions that Indonesian speakers recognize and use, but they are not ubiquitous. They occupy a middle band of the frequency spectrum: common enough to be part of the shared linguistic repertoire, rare enough that each occurrence carries noticeable expressive weight. This profile has practical implications for anyone building language technology for Indonesian, from machine translation systems to language-teaching materials, because it suggests that animal idioms are worth teaching and modeling but cannot be treated as high-frequency vocabulary.

The second major finding is the one most likely to make readers sit up: negative sentiment overwhelms the Indonesian idiomatic zoo. When the researchers scored the expressions for emotional valence, the vast majority came out negative. The office rat steals, the night butterfly transgresses, and a whole roster of other creatures stands in for laziness, greed, stupidity, and deceit. This asymmetry is not unique to Indonesian, and it echoes a pattern documented in English and other languages, where animal idioms more often insult than compliment. But seeing the pattern confirmed quantitatively in a large Indonesian corpus gives it new weight. It suggests that the metaphorical use of animals is, across very different languages and cultures, a vehicle humans reach for when they want to condemn rather than praise.

Perhaps the most intriguing null result of the study is what the researchers did not find. They tested whether particular types of animals were statistically associated with particular sentiments, for example whether rodents or insects skew more negative than mammals or birds. No statistically significant association emerged between sentiment and specific animal types. Negativity, in other words, is spread across the menagerie rather than concentrated in any one taxonomic corner of it. The cultural work of disparagement, in Indonesian idiom at least, is performed by the act of comparing a person to an animal at all, not by the choice of which animal. That finding challenges a common intuition that certain creatures carry inherently negative symbolic loads and instead points toward a more general cognitive mechanism: dehumanizing comparison itself is the insult.

The study also speaks to the degrees of ambiguity that idioms display in real text. Some expressions are almost always used figuratively, so a reader encountering them rarely mistakes the office rat for an actual rodent. Others retain a live literal reading, and context must decide. Measuring this ambiguity matters beyond linguistics. Natural language processing systems struggle with idioms precisely because their meanings are not compositional, so knowing which Indonesian idioms are strongly fixed and which are context-dependent provides a roadmap for improving Indonesian-language tools, from sentiment analysis to idiom-aware machine translation. The authors explicitly frame their corpus-based insights as a contribution to cross-linguistic idiom studies and semantic analysis, and the dataset they have assembled offers a baseline that future comparative work can build on.

There is also a broader cultural story here. Idioms are fossils of folk knowledge, preserving how a speech community once saw its animals, its offices, and its moral failures. The fact that Indonesian speakers describe adolescent romance with monkeys and corruption with rats tells us something about which images resonate in Indonesian culture, and the corpus method tells us how alive those images still are in contemporary text. The research, funded by the Faculty of Humanities at Universitas Diponegoro under its international publication program, was conducted entirely on open-access data licensed for non-commercial use, and the authors report no competing interests. As computational methods spread through the humanities, studies of this kind show how a seemingly whimsical question, why does Indonesian keep so many animals in its idioms, can yield rigorous answers about frequency, ambiguity, and sentiment, and can place a major world language firmly on the map of figurative language research.

Subject of Research: Corpus-linguistic profiling of animal idiomatic expressions in Indonesian, examining their frequency, ambiguity, and sentiment

Article Title: An Indonesian idiomatic zoo: profiling the distribution of animal idiomatic expressions in an Indonesian corpus

Article References: An Indonesian idiomatic zoo: profiling the distribution of animal idiomatic expressions in an Indonesian corpus. (n.d.). https://doi.org/10.1038/s41599-026-09311-4

Image Credits: AI Generated

DOI: 10.1038/s41599-026-09311-4

Keywords: Indonesian language, idioms, corpus linguistics, animal metaphors, sentiment analysis, lexical semantics, figurative language, computational linguistics, LCC Indonesian corpus, cross-linguistic comparison, semantic analysis, linguistics