There are about 7,000 languages currently spoken on our planet. If a language no longer has any speakers it is classified as “extinct” as opposed to a “dead language” which is one that is known but which has no native speakers.
At its height, Latin was spoken by about 25% of the world’s population. Now there are no native speakers. That is a shocking decline of what was the world’s foremost language. How did that happen?
In early A.D. the Catholic Church gained power and influence over the Roman Empire. Latin was the main language of the Church and thus became the primary language of the Romans. As the Roman Empire spread to Western Europe, Latin spread with it. Latin did not completely displace the local languages, but instead became the lingua franca of the empire. Local languages often survived underneath and alongside Latin. Note that Latin did not successfully spread to the eastern part of the Roman Empire. There the Eastern Orthodox Church was dominant and Greek was the language of that church and thus Greek was the lingua franca of the eastern Roman Empire.
Because Latin existed along side local languages in many parts of the empire, Latin had a lot of regional variation. While the Roman Empire held together, however, Latin remained a distinct language due to a process called “dialect leveling.” As people moved from place to place within the Empire and as trade occurred among people with different dialects came into contact, the differences in language variation tended to drop off. We see this in the U.S. with English – while there are regional differences, there is so much people movement (and now media) that English has remained a single language without too much variation.
When the Roman Empire collapsed trade and people movement within the western Roman Empire declined as well. Europe fell into the dark ages. Dialect leveling fell away and Latin morphed into various vernacular dialects that became the “Romance Languages,” the main ones being Italian, French, Portuguese, Spanish and Romanian. Thus, Latin didn’t “die” but rather it split and it changed. For example, while it is impossible to pinpoint exactly, what is now known as “Italian” didn’t exist until the 13th century and modern “French” came into being in the 17th century (old and middle French preceded it).
Latin still exists today in its classical form due to its use by the Catholic Church, scholars and scientists over the centuries. While Latin no longer is used in Catholic masses, it remains a factor in law and science.