← Latest papers
💬 NLP

Complexity counts: global and local perspectives on Indo-Aryan numeral systems

This paper quantifies the unusually high complexity of Indo-Aryan numeral systems compared to global norms, investigates the socio-geographic factors driving their persistence, and demonstrates that despite their non-transparent forms, these systems still adhere to cross-linguistic pressures for efficient communication.

Original authors: Chundra Cathcart

Published 2026-04-07
📖 5 min read🧠 Deep dive

Original authors: Chundra Cathcart

Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine you are trying to learn a new language. You pick up a dictionary and look at the numbers. In English, it's like a well-organized Lego set: if you know "twenty" and "one," you can easily build "twenty-one." If you know "ninety" and "nine," you can build "ninety-nine." It's predictable, logical, and follows a clear blueprint.

Now, imagine picking up a dictionary for Hindi or Urdu. Suddenly, the Lego set has been melted down and reshaped into strange, organic blobs. "Twenty-one" isn't built from "twenty" and "one"; it's a completely new, unpredictable word. "Ninety-one" doesn't sound like "ninety" at all. It's as if the language decided to throw away the instruction manual and just memorize every single number as a unique, isolated puzzle piece.

This is the story of Indo-Aryan numeral systems (languages like Hindi, Bengali, Gujarati, and Urdu), and it's exactly what Chundra Cathcart's paper is investigating.

Here is the breakdown of the paper in simple terms, using some creative analogies:

1. The "Mystery Box" of South Asian Numbers

Most of the world's languages are like transparent glass boxes. You can see inside and understand how the parts fit together (e.g., four-teen = four + ten).

South Asian languages, however, are like opaque, locked mystery boxes. The numbers from 1 to 99 are "non-transparent." You cannot take the word for 90 and the word for 1 and smash them together to get the word for 91. They are "fused" or "irregular."

  • The Analogy: Think of English numbers as a recipe (Mix 2 cups of flour + 1 egg = Cake). You can make any cake if you know the recipe. Indo-Aryan numbers are like secret family recipes where the chef just memorized the taste of 91 specific cakes. If you want to know what "91" tastes like, you have to memorize it specifically; you can't just guess it based on "90" and "1."

2. The Global Map: A "Hotspot" of Complexity

The author didn't just guess this; they used a massive database of languages from around the world to measure "complexity."

  • The Analogy: Imagine a weather map where "storms" represent linguistic complexity. Most of the world is sunny and calm (simple, regular numbers). But when you zoom in on South Asia, you see a massive, swirling hurricane of complexity.
  • The study proves that this isn't just a small storm; it's the most intense "weather system" for numbers on the entire planet. Interestingly, this complexity is mostly found in the Indo-Aryan family (like Hindi). Neighboring languages (like Dravidian languages) are much calmer and more regular, even though they live in the same region.

3. Why Did This Happen? (The "Social Network" Theory)

The paper asks: Why did these languages get so complicated, and why did they keep it?

  • The Theory: The author suggests it's about social pressure and density.
  • The Analogy: Imagine a bustling, crowded city market (the core Indo-Aryan area). Everyone is talking to everyone else, trading goods, and negotiating prices. In this dense network, people need to be very precise. Over centuries, the "noise" of the market and the constant interaction caused the numbers to mutate and become unique, like a secret handshake that only the locals know.
  • The Contrast: Now, imagine a small, isolated village high in the mountains (the Hindu Kush region). These people are cut off from the main market. They didn't develop these crazy, complex numbers. In fact, they often switched to a simpler system (counting by 20s instead of 10s) because they didn't need the same level of intricate precision or didn't have the social pressure to maintain the "secret code."

4. The Paradox: Chaos with a Hidden Order

Here is the most surprising part of the paper. Even though these number systems look like a chaotic mess, they actually follow a hidden rule of efficiency.

  • The Analogy: Think of a busy airport. The terminal looks chaotic, but there's a hidden logic: the most important flights (the most common numbers) get the most direct, specialized gates, even if those gates look weird. The less important flights (rare, huge numbers) get the standard, boring gates.
  • The Finding: In Indo-Aryan languages, the numbers we use every day (like 1, 2, 3, 10, 20) are the most irregular and complex. The numbers we use rarely (like 87 or 93) are actually becoming slightly more regular and predictable.
  • Why? Because our brains are lazy! We use the common numbers so often that we don't need to "calculate" them; we just memorize them as unique sounds. The rare numbers are used so little that the language naturally tries to make them easier to guess. It's a trade-off: High frequency = High complexity (because we know them by heart); Low frequency = High transparency (because we need to guess them).

5. The Takeaway

This paper is a call to action for linguists. For a long time, researchers have ignored these "messy" number systems because they are hard to analyze. They focused on the "clean" languages.

But this paper argues that Indo-Aryan languages are the ultimate stress test for human cognition. They show us that humans are incredibly good at tolerating complexity if it's part of their culture. It's like a gym for the brain: these speakers are lifting heavy linguistic weights every day without breaking a sweat.

In short:

  • The Problem: South Asian numbers are weirdly complex and don't follow simple rules.
  • The Cause: Dense social networks in the core regions kept this complexity alive, while isolated areas lost it.
  • The Twist: Despite the chaos, the system is actually efficient. The most common numbers are the most complex, and the rare ones are simpler, proving that human brains are masters at balancing memory and logic.

The paper concludes that we should stop ignoring these "messy" systems. They aren't broken; they are just a different, highly evolved way of organizing the world, showing us just how flexible and resilient human language can be.

Drowning in papers in your field?

Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.

Try Digest →