Why Do French People Say ‘Quatre-vingt-dix’ Instead of ‘Nonante’?

If you've ever learned French, you’ve probably been baffled by the way the French count numbers, especially when they hit 70, 80, and 90. While our Belgian and Swiss friends use the more logical septante (70), huitante or octante (80), and nonante (90), the French go with soixante-dix (60+10), quatre-vingts (4x20), and quatre-vingt-dix (4x20+10).

But why? Why does France insist on this bizarre math when other French-speaking countries use simpler words? Let’s dive into the history, logic (or lack thereof), and quirks of the French number system!

A Bit of History: The Origins of the French Counting System

To understand why the French say quatre-vingt-dix instead of nonante, we need to go way back—before modern French even existed. The roots of the French number system can be traced to two main influences:

1. The Ancient Celts and the Base-20 System

The Celtic peoples, who once occupied much of what is now France, used a vigesimal (base-20) counting system. Instead of counting in tens like we do today, they counted in twenties. Traces of this can still be found in languages like Danish, where 80 is firs (short for fire-sinds-tyve, meaning "four times twenty").

This Celtic influence likely played a role in shaping the old French number system, especially for numbers like 80 (quatre-vingts = "four twenties").

2. The Romans and the Base-10 System

Meanwhile, the Romans, who conquered Gaul (modern-day France), brought their decimal (base-10) system. This is the system we use today, where numbers are built in tens (10, 20, 30, etc.).

As Latin evolved into Old French, the French adopted the base-10 system for most numbers—but for some reason, the old Celtic base-20 influence stuck around, especially for numbers above 60.

Why Did France Stick With ‘Quatre-Vingt-Dix’?

By the Middle Ages, both systems coexisted. Some regions of France used nonante (90) and septante (70), while others used soixante-dix (60+10) and quatre-vingt-dix (4x20+10). But then something happened that solidified the quirky counting system we know today:

1. The Power of Paris

France was made up of many dialects and regional languages, but Paris, the capital, had the most influence. The Parisians used the soixante-dix / quatre-vingt-dix system, and because Paris was the political, cultural, and economic center of France, its version of French became the standard.

2. The French Academy’s Influence

The Académie Française, which was established in 1635 to regulate the French language, helped reinforce Parisian French as the official standard. The simpler septante, octante, nonante words used in other regions were slowly phased out in favor of the complex counting system still used today.

3. The French Revolution and Standardization

During the French Revolution (1789–1799), France made major efforts to unify the country under one language. They even tried to introduce a completely decimal-based system for time and measurements, but while the metric system stuck, their attempt to change the way people counted didn’t last. The traditional soixante-dix and quatre-vingt-dix survived, while septante and nonante faded in France.

But Wait—What About Belgium, Switzerland, and Canada?

Not all French-speaking countries followed France’s lead. In Belgium, Switzerland, and parts of Canada, people still say:

✅ Septante (70) instead of soixante-dix
✅ Nonante (90) instead of quatre-vingt-dix

As for 80, Belgium mostly uses quatre-vingts, while Switzerland leans towards huitante or octante in some areas.

So why did these countries keep the simpler system? Because they weren’t under the direct linguistic influence of Paris, and their versions of French evolved independently. In fact, in many former French colonies, nonante is still used informally because it's just easier!

Will France Ever Change to ‘Nonante’?

Probably not. The quatre-vingt-dix system has been around for centuries, and while French people agree that nonante would be much simpler, language is deeply tied to tradition. Even though septante and nonante are easier to learn, most French speakers in France aren’t about to give up their quirky numbers anytime soon.

That said, many French people are aware of the alternative system used in Belgium and Switzerland, and if you say nonante in France, they’ll understand you—they just might find it a little odd!

The reason why the French say quatre-vingt-dix instead of nonante is rooted in history, Celtic influence, and the centralization of the French language in Paris. While other French-speaking regions stuck with a more logical system, France embraced its complicated math-based numbers—and hasn’t looked back since.

So, whether you prefer the mathematical challenge of quatre-vingt-dix or the simplicity of nonante, at least now you know where this strange number system comes from!