1. Sanskrit: The liturgical language of Hinduism, Buddhism, and Jainism, with a rich literary tradition including the Vedas, Upanishads, and the epic Ramayana and Mahabharata.
2. Latin: The language of ancient Rome, the foundation for many Romance languages like Spanish, French, Italian, and Portuguese. It's also the language of the Catholic Church.
3. Ancient Greek: The language of the ancient Greek civilization, renowned for its philosophical, scientific, and literary achievements. Its literature includes works by Homer, Plato, Aristotle, and Sophocles.
4. Hebrew: The sacred language of Judaism, with a rich literary tradition including the Hebrew Bible and the Talmud. Modern Hebrew is a revival of this ancient language.
5. Arabic: The liturgical language of Islam, with a rich literary tradition including the Quran, Hadith, and poetry.
6. Avestan: The sacred language of Zoroastrianism, an ancient Iranian religion.
7. Old Church Slavonic: The liturgical language of the Eastern Orthodox Church, with a significant influence on other Slavic languages.
8. Classical Chinese: The written form of Chinese used in China from the Qin dynasty (221 BC) to the Qing dynasty (1912). It's a complex system of characters with a rich literary tradition.
9. Egyptian Hieroglyphs: The writing system of ancient Egypt, with a rich system of symbols representing both sounds and meanings.
10. Akkadian: A Semitic language spoken in ancient Mesopotamia. The Akkadian language was used for a wide range of literature, including religious texts, epics, and legal documents.
It's important to note that this list is not exhaustive, and there are other languages that could be considered classical depending on the criteria used.