For the use of Aramaic in the Christian Bible, see Aramaic of Jesus.
Biblical Aramaic is the form of Aramaic that is used in the books of Daniel, Ezra and a few other places in the Hebrew Bible.

It should not be confused with the Aramaic paraphrases, explanations and expansions of the Jewish scriptures, which are known as targumim.

History:

As Old Aramaic had served as a lingua franca in the Neo-Assyrian Empire from the 8th century BCE, linguistic contact with even the oldest stages of Biblical Hebrew is easily accounted for.

Jews in the exile of Babylon:

During the Babylonian exile, Aramaic became the language spoken by the Jews, and Aramaic square script replaced the Paleo-Hebrew alphabet.

After the Achaemenid Empire captured Babylon, Aramaic became the language of culture and learning.

King Darius I declared Imperial Aramaic to be the official language of the western half of his empire in 500 BCE, and it is that Imperial Aramaic that forms the basis of Biblical Aramaic.

Biblical Hebrew was gradually reduced to the status of a liturgical language and a language of theological learning, and the Jews of the Second Temple period would have spoken a western form of Old Aramaic until their partial Hellenization from the 3rd century BCE and the eventual emergence of Middle Aramaic in the 3rd century CE.

Biblical Aramaic’s relative chronology has been debated mostly in the context of dating the Book of Daniel. In 1929, Rowley argued that its origin must be later than the 6th century BCE and that the language was more similar to the Targums than to the Imperial Aramaic documents available at his time.

Others have argued that the language most closely resembles the 5th century Elephantine papyri and so is a good representative of typical Imperial Aramaic.

Kenneth Kitchen takes an agnostic position and states that the Aramaic of the Book of Daniel is compatible with any period from the 5th to early 2nd century BCE.

Aramaic and Hebrew:  

Biblical Hebrew is the main language of the Hebrew Bible. Aramaic accounts for only about 250 verses out of a total of over 23,000.

Biblical Aramaic is closely related to Hebrew, as both are in the Northwest Semitic language family. Some obvious similarities and differences are listed below: