Latin is an Italic language that was used in Ancient Rome. Short Latin texts have been found from about the 5th century BC and longer texts from about the 3rd century BC.

Classical Latin was used in the 1st century BC and was the official language of the Roman Empire. It was widely used in the western part of the Mediterranean. The languages known as Romance languages developed from the spoken version, called Vulgar Latin.

Latin was very important to Christianity for many centuries. It is still spoken today during some religious activities. It is an official language in the Vatican, where the Pope leads the Roman Catholic Church.[4] People in the Vatican sometimes speak to one another in Latin (if they have different first languages). The mass of the Catholic Church may be done entirely in Latin. This is the Mass of the Roman Rite (Extraordinary Form).

Latin is called a dead language because no one speaks Latin as a first language anymore. Even though it is a dead language, it is not an extinct language because it is still used in daily life by some people. In fact, many people still study it in school. Latin is still useful because it shows how society and the language used to work. Knowing Latin makes it easier to learn the Romance languages.

People still read Latin classics such as the poems of Virgil, the memoirs of Caesar and the speeches of Cicero. Also, Latin is widely used as an international auxiliary language, notably in the Catholic Church, and by biologists when describing and naming new species.

Latin is still used in taxonomy to give scientific names to species and groups of species of living things. Some terms used in medicine to name parts of the body (such as bones) and diseases are also written in Latin.

There are three types of Latin: Classical Latin, Vulgar Latin, and Ecclesiastical Latin. Classical Latin was used by the educated Romans and is still studied around the world. Vulgar Latin was the more common spoken variety used by the common Romans and was learned by the peoples conquered by the Romans. Ecclesiastical Latin is common in Italian schools and still used by the Roman Catholic Church.

Latin was the most important language in most of Europe in the Middle Ages. It was taught in many European schools, and all universities used Latin as the teaching language. Latin began to lose its importance in the Reformation, but it was still often used by authors of scientific books and encyclopedias. Until about 1900 many universities accepted dissertations written in Latin.

As people from other regions of Europe learned Vulgar Latin during Roman conquests, each region developed its own language, a simplified form of Latin. Those languages are called Romance languages, and they are still spoken today. The five Romance languages with the largest number of speakers are Spanish, French, Portuguese, Italian, and Romanian. The Romance languages are very similar to one another, and speakers of one Romance language can understand many words and sentences (in both texts and spoken conversations) from another Romance language. For example, speakers of Portuguese can often understand Spanish. It can be said that the Romance languages are modern dialects of Latin.

Latin has a similar inflection structure to Ancient Greek but a different alphabet.

Latin has seven different noun cases: nominative, vocative, accusative, genitive, dative, ablative and locative. The vocative case is almost always the same as the nominative case; however, if the nominative ends in -us, it changes to -e, and if the nominative ends in -ius, it changes to -i. The locative takes the form of the dative. Latin nouns are declined, or changed, according to how they are used in the sentence. A noun can be declined five different ways. These ways are called declensions. The declensions are numbered 1 through 5 (first declension, second declension etc), each having different endings that identify the noun's declension. When a noun is declined, twelve forms are made, two for each of the noun cases (the locative is omitted).

A similar thing is done to verbs, called conjugation. When a verb is conjugated, six forms are made. There are five factors that can change a verb: person, number, tense, voice, and mood. In all, there are 120 possible forms Latin verbs.

Latin used to be written on plates of wax. There was little space and so words were run together, with no space between words. Sometimes papyrus was used, but this was expensive. Punctuation was an ancient idea but came to Latin later.[5] Lowercase letters (small letters) are relatively modern inventions. The Roman alphabet was derived from the Etruscan language.

The following is the introduction to the Metamorphoses by Ovid (Book 1, lines 89–100); it describes the Golden Age.

AVREA•PRIMA•SATA•EST•ÆTAS•QVAE•VINDICE•NVLLOSPONTE•SVA•SINE•LEGE•FIDEM•RECTVMQVE•COLEBATPOENA•METVSQVE•ABERANT•NEC•VERBA•MINANTIA•FIXOAERE•LEGEBANTVR•NEC•SVPPLEX•TVRBA•TIMEBATIVDICIS•ORA•SVI•SED•ERANT•SINE•VINDICE•TVTINONDVM•CÆSA•SVIS•PEREGRINVM•VT•VISERET•ORBEMMONTIBVS•IN•LIQVIDAS•PINVS•DESCENDERAT•VNDASNVLLAQVE•MORTALES•PRÆTER•SVA•LITORA•NORANTNONDVM•PRÆCIPITES•CINGEBANT•OPPIDA•FOSSAENON•TVBA•DIRECTI•NON•ÆRIS•CORNVA•FLEXINON•GALEAE•NON•ENSIS•ERANT•SINE•MILITIS•VSVMOLLIA•SECVRAE•PERAGEBANT•OTIA•GENTES

Aurea prima sata est aetas, quae vindice nullo,
sponte sua, sine lege fidem rectumque colebat.
Poena metusque aberant nec verba minantia fixo
aere legebantur, nec supplex turba timebat
iudicis ora sui, sed erant sine vindice tuti.
Nondum caesa suis, peregrinum ut viseret orbem,
montibus in liquidas pinus descenderat undas,
nullaque mortales praeter sua litora norant.
Nondum praecipites cingebant oppida fossae,
non tuba directi, non aeris cornua flexi,
non galeae, non ensis erant: sine militis usu
mollia securae peragebant otia gentes.

After the fall of the Roman Empire, many people still used Latin. Scholars such as Thomas Aquinas, Petrarch, Erasmus, Luther, Copernicus, Descartes and Newton wrote in Latin. As an example, Hugo Grotius published his De jure belli ac pacis (On the Law of War and Peace) in 1625, which is one of the bases of international law.