Think of it like the transition from childhood to adulthood. There’s no one morning you wake up and are suddenly an adult. It’s a gradual process of change, marked by milestones—a growth spurt here, a new responsibility there. The evolution of a language is much the same. So, to find our answer, we can’t look for a single date, but rather for the key milestones that mark the birth of new languages from the body of the old.

The Lingering Ghost of Rome: From Classical to Vulgar Latin

First, we need to clarify what we mean by “Latin.” The language of Roman senators like Cicero and poets like Virgil was Classical Latin. It was a highly structured, formal, and literary language. But it wasn’t what the average Roman soldier, merchant, or farmer spoke in the streets of Rome, let alone in the far-flung colonies of Gaul (modern France) or Hispania (modern Spain).

What they spoke was Vulgar Latin (from vulgus, meaning “the common people”). It was simpler, more dynamic, and varied significantly by region. This everyday spoken language was the true parent of the Romance languages. The differences were clear even then:

• A Classical Roman would use equus for “horse”, but the common soldier preferred caballus (originally meaning “nag” or “workhorse”). This is why we have French cheval and Spanish caballo.
• To “eat” in Classical Latin was edere. In Vulgar Latin, the more descriptive verb manducare (“to chew”) became popular. This gave us the French verb manger.
• The word for “head”, caput, was often replaced in everyday speech by testa (originally “earthen pot”), a slang term that stuck. It became the French tête and Italian testa.

As long as the Roman Empire was a powerful, centralized entity, its administrative and educational structures kept these regional dialects in check. They were all still, recognizably, dialects of Latin.

The Cracks Appear: How the Fall of an Empire Birthed New Tongues

The crucial turning point was the collapse of the Western Roman Empire in the 5th century AD. With Roman administration gone, political unity shattered. The roads fell into disrepair, trade dwindled, and communication between regions broke down. The linguistic glue that held the empire together dissolved.

Isolated from each other, the Vulgar Latin dialects of Gaul, Hispania, and other former provinces began to drift apart more rapidly. This divergence was supercharged by the arrival of new rulers.

• In Gaul, the invading Franks, a Germanic tribe, took over. While they eventually adopted the local Romance speech, they left their mark on its vocabulary. Words like guerre (war, from Frankish *werra), riche (rich, from *rīkī), and the color blanc (white, from *blank) are all Germanic loanwords.
• In Hispania, the Visigoths (and later, the Moors with Arabic) had a similar effect. The Spanish word for war, guerra, shares the same Germanic root as its French counterpart. The word for “clothes”, ropa, comes from a Gothic word for “spoils” or “loot.”

For several hundred years, from roughly 500 to 800 AD, these dialects evolved in the dark. People were speaking a language that was no longer Latin, but they didn’t have a name for it yet. Crucially, the only language for writing, religion, and official business remained Latin—a fossilized, learned language that was increasingly alien to what people actually spoke.

A Conscious Uncoupling: When People Realized They Weren’t Speaking Latin Anymore

The true “birth” of French and Spanish can be pinpointed to the moment when people became aware of this linguistic split and acknowledged that the common tongue was a separate entity worthy of being written down. This happened at different times in different places.

The French Case: The Oaths of Strasbourg (842 AD)

This is arguably the most famous “birth certificate” of a Romance language. After the death of Charlemagne, his grandsons fought over the empire. Two of them, Charles the Bald and Louis the German, formed an alliance. To ensure their armies understood the pact, the oaths of loyalty were sworn and written down not in Latin, but in the vernacular languages of their soldiers.

Louis, king of the East Franks, read his oath in the local Romance tongue so Charles’s men could understand. This text, the Oaths of Strasbourg, is considered the first surviving document written in Old French.

“Pro Deo amur et pro christian poblo et nostro commun salvament, d’ist di en avant, in quant Deus savir et podir me dunat, si salvarai eo cist meon fradre Karlo et in ajudha et in cadhuna cosa…”

(For the love of God and for the Christian people and our common salvation, from this day forward, as God gives me knowledge and power, I will protect this brother of mine, Charles, with my help and in everything…)

Look closely. It’s not Latin (which would be something like “Pro Dei amore et pro populo christiano et nostra salute communi…”), but it’s not modern French either. It is something new: lingua romana rustica, the “rustic Roman language”, now officially recognized.

The Spanish Case: The Glosas Emilianenses (c. 975-1000 AD)

The first flickers of written Spanish appear a bit later and in a more humble setting. In the monastery of San Millán de la Cogolla, a monk was reading a religious text in Latin. Finding some passages difficult, he scribbled notes, or “glosses” (glosas), in the margins and between the lines to explain the Latin words.

These notes, the Glosas Emilianenses, were written in his local Navarro-Aragonese dialect of Ibero-Romance—the precursor to modern Spanish. He wasn’t trying to write a new language; he was just trying to understand an old one. But in doing so, he provided the first written proof of Spanish.

For instance, where the Latin text used the formal word invenitur (“is found”), the monk glossed it with the more common “se troba”, the ancestor of the modern Spanish verb trobar (“to find”, often in a poetic sense). He was translating Latin into the language of his own mind, a language we can now recognize as a primitive form of Spanish.

The Verdict: A Timeline, Not a Timestamp

So, when did Latin become French and Spanish? There is no single answer, but there is a clear timeline of transformation:

1. ~200 BC – 400 AD: Vulgar Latin spreads across Europe and develops distinct regional characteristics.
2. ~400 – 800 AD: The political collapse of Rome accelerates linguistic divergence. The spoken languages of Gaul and Hispania drift far from Latin, becoming what we call Proto-Romance.
3. 9th – 10th Centuries: The “Aha!” moment. The Oaths of Strasbourg (842) and the Glosas Emilianenses (c. 975) show a conscious recognition that the vernacular is a separate language from Latin. This is the birth of Old French and Old Spanish as written tongues.
4. 11th Century Onward: These new languages develop their own literature (like The Song of Roland in French and El Cantar de mio Cid in Spanish), slowly become standardized, and eventually replace Latin in all functions of life.

The story of Latin’s evolution is a powerful reminder that languages are not static relics. They are fluid, dynamic systems that are constantly being shaped by history, culture, and the everyday conversations of millions of people. They don’t die so much as they transform, leaving behind children and grandchildren who carry on their legacy in new and beautiful ways.