Classical language

According to the definition by George L. Hart, a classical language is any language with an independent literary tradition and a large body of ancient written literature.
Classical languages are usually extinct languages. Those that are still in use today tend to show highly diglossic characteristics in areas where they are used, as the difference between spoken and written language has widened over time.
In the context of traditional European classical studies, the "classical languages" refer to Greek and Latin, which were the literary languages of the Mediterranean world in classical antiquity.
Greek was the language of Homer and of classical Athenian, Hellenistic and Byzantine historians, playwrights, and philosophers. It has contributed many words to the vocabulary of English and many other European languages, and has been a standard subject of study in Western educational institutions since the Renaissance. Latinized forms of Ancient Greek roots are used in many of the scientific names of species and in other scientific terminology. Koine Greek, which served as a lingua franca in the Eastern Roman Empire, remains in use today as a sacred language in some Eastern Orthodox churches.
Latin became the lingua franca of the early Roman Empire and later of the Western Roman Empire. Despite the decline of the Western Roman Empire, the Latin language continued to flourish in the very different social and economic environment of the Middle Ages, not least because it became the official language of the Roman Catholic Church. In Western and Central Europe and in parts of northern Africa, Latin retained its elevated status as the main vehicle of communication for the learned classes throughout the Middle Ages and subsequently; witness especially the Renaissance and Baroque periods. And well into the 21st century, Latin is still taught in the United States, mostly in elite private schools.
Latin was not supplanted for scientific purposes until the 18th century, and for formal descriptions in zoology as well as botany it survived to the later 20th century. The modern international binomial nomenclature holds to this day: taxonomists assign a Latin or Latinized name as the scientific name of each species.
In terms of worldwide cultural importance, Edward Sapir in his 1921 book Language extends the list to include classical Chinese, Arabic, and Sanskrit:
In this sense, a classical language is a language that has a broad influence over an extended period of time, even after it is no longer a colloquial mother tongue in its original form. If one language uses roots from another language to coin words (in the way that many European languages use Greek and Latin roots to devise new words such as "telephone", etc.), this is an indication that the second language is a classical language.
In comparison, living languages with a large sphere of influence are known as world languages.
The following languages are generally taken to have a "classical" stage. Such a stage is limited in time and is considered "classical" if it comes to be regarded as a literary "golden age" retrospectively. Thus, Classical Greek is the language of 5th to 4th century BC Athens and, as such, only a small subset of the varieties of the Greek language as a whole. A "classical" period usually corresponds to a flowering of literature following an "archaic" period, such as Classical Latin succeeding Old Latin, Classical Sumerian succeeding Archaic Sumerian, Classical Sanskrit succeeding Vedic Sanskrit, Classical Persian succeeding Old Persian. This is partly a matter of terminology, and for example Old Chinese is taken to include rather than precede Classical Chinese. In some cases, such as those of Persian and Tamil, the "classical" stage corresponds to the earliest attested literary variant.