The Appendix Probi: When ‘Bad’ Latin Won

Imagine a frustrated school teacher in the 3rd century AD. The Roman Empire is vast, but the purity of its language is crumbling. In a desperate attempt to hold back the tide of “lazy” pronunciation and “improper” grammar, this anonymous teacher sits down and writes a list. It is a catalogue of errors—a cheat sheet of 227 pairs of words following a strict pattern: “Say this, not that.”

This document, known today as the Appendix Probi, was intended to be a shield protecting Classical Latin from corruption. Ironically, it became something far more valuable. It is the linguistic equivalent of a fossil record, preserving the exact moment when Latin began to fracture and evolve into the languages spoken by nearly a billion people today.

To the author, the list was a collection of mistakes. To modern linguists, it is the birth certificate of Spanish, Italian, French, Portuguese, and Romanian. It proves that the “bad” Latin of the streets was destined to win.

What is the Appendix Probi?

The manuscript dates back to roughly the 3rd or 4th century AD. It gets its name because it was found appended to the back of a grammar work by Valerius Probus, a famous scholar, though Probus himself didn’t write it. The author was likely a schoolmaster or a scribe in Rome or Africa who was annoyed by the way people were butchering the masterful tongue of Cicero and Virgil.

The format is repetitive and prescriptive. It follows the structure: [Classical Form] non [Vulgar Form].

For example:

• Speculum non speclum
• Columna non colomna
• Calida non calda

Essentially, the author was saying: “The word is speculum, not speclum!” But the fact that he had to write it down tells us something crucial: everyone was already saying speclum. The dam had already broken.

The “Laziness” That Created Spanish and Italian

Language evolves according to the Principle of Least Effort. Speakers naturally look for shortcuts to make communication faster and physically easier for the mouth to produce. The Appendix Probi is arguably the best historical evidence of this principle in action.

Let’s look at three specific linguistic mechanisms found in the list that show how Classical Latin transformed into Romance languages.

1. Syncope: The Case of the Vanishing Vowel

One of the most common complaints in the Appendix is the dropping of unstressed vowels in the middle of words. This process is called syncope.

The Entry: Speculum non speclum (Mirror)

In Classical Latin, speculum was pronounced with three syllables. But in casual speech (Vulgar Latin), the stress fell heavily on the first syllable. The unstressed ‘u’ in the middle was weak, and over time, speakers stopped pronouncing it entirely. Speculum became speclum.

The Result: This “mistake” became the standard.

In Italian, speclum evolved into specchio.

In Spanish, the ‘cl’ sound shifted, and it became espejo.

If the Romans had listened to the grammar teacher, modern Italian and Spanish might sound vastly different today.

2. Diminutives Taking Over

Sometimes, speakers stop using the standard word entirely, preferring a “cuter” or smaller version of the word, known as a diminutive.

The Entry: Auris non oricla (Ear)

The Classical word for “ear” was auris. However, in the streets, people preferred the diminutive form auricula (little ear). Over time, auricula underwent sound changes (the ‘au’ became ‘o’, and the unstressed ‘u’ dropped out) to become oricla.

The author of the Appendix hated this. He wanted people to use the proper, dignified auris. He failed. The word auris essentially went extinct in daily speech, surviving only in scientific words like “aural.”

The Result:

Oricla became oreille in French.

It became orecchio in Italian.

It became oreja in Spanish.

3. Sound Shifts: The Vowel Drift

The way vowels were pronounced began to shift radically between the Classical and Vulgar periods.

The Entry: Columna non colomna (Column)

Here we see the ‘u’ opening up into an ‘o’. This was part of a massive restructuring of the vowel system where the precise length of vowels (short vs. long) stopped mattering, and the quality (tone) took over.

The Result: The “error” colomna is the direct ancestor of the Italian colonna and the French colonne.

Why “Bad” Latin Won

Why did the uneducated masses win this tug-of-war against the educated elite? The answer lies in the nature of language itself. Language is not a set of rules carved in stone; it is a democracy of the living.

The overarching language spoken by the people—soldiers, merchants, slaves, and farmers—is known to linguists as Vulgar Latin (from vulgaris, meaning “common”). As the Roman Empire expanded, this spoken version of the language traveled to Iberia, Gaul, and Dacia. Isolated from the strict schooling of Rome, these dialects drifted further apart.

The author of the Appendix Probi was a prescriptivist. He believed there was one correct way to speak and that deviation was degradation. However, history favors descriptivism—the observation of how language is actually used.

When the Roman Empire fell, the centralized education system collapsed with it. There was no one left to enforce the rules of the Appendix. The “errors” flourished because they were efficient, catchy, and universally understood.

From Mistakes to Masterpieces

It is fascinating to trace modern vocabulary back to these specific complaints. Here is a quick table of how the “correction” failed and the “error” prevailed:

Classical Latin (The “Correct” Way)	Appendix Probi “Error”	English Meaning	Modern Descendant
Oculus	Oclus	Eye	Ojo (Spanish), Occhio (Italian)
Vinea	Vinia	Vine/Vineyard	Viña (Spanish), Vigna (Italian)
Calida	Calda	Hot/Warm	Caldo (Italian), Chaude (French)

Conclusion: The Ghost of the Grammarian

We don’t know who the author of the Appendix Probi was. He likely died believing that the Latin language was being destroyed by the ignorance of the youth and the uneducated.

But in a way, he gave us a gift. Without his complaints, we would have very little documentation of how Latin resulted in the diverse tapestry of European languages we hear today. He thought he was writing a list of garbage; instead, he was writing the first draft of Dante’s Divine Comedy and Cervantes’ Don Quixote.

The next time someone corrects your grammar—perhaps for saying “who” instead of “whom”—remember the Appendix Probi. You aren’t necessarily speaking incorrectly; you might just be a pioneer of the next great language evolution.