The Aramaic script was used for writing the Aramaic language, which was the trade language of the Middle East from about 1000 BC to about 1000 AD. Aramaic writing is derived from the Phoenician script. Because the evolution from one to the other was a continuous process over about 2000 years it is difficult to divide it neatly into 'uniquely Phoenician' and 'uniquely Aramaic' blocks; however, it is generally agreed that a divergence into two distinct scripts was evident by about the 8th century BC. Both the Phoenician and Aramaic scripts were the antecedents of a large and geographically diverse family of writing systems. Many of the scripts used today for writing Indo-European languages are part of this family. Again, because the two scripts were so closely related it is not clear exactly which writings systems descended from each. Conventionally, the scripts used in Western Europe and the Mediterranean are called 'Phoenician-derived' and those used in the Middle East and Central/South Asia are called 'Aramaic-derived'.
Imperial Aramaic was both the official language of the Persian Empire from the 5th to the 3rd centuries BC, and the script used for writing this language. It was used throughout modern-day Iran, Afghanistan, Pakistan, Thrace and Macedonia, Iraq, northern Saudi Arabia, Jordan, Palestine, Israel, Lebanon, Syria, and parts of Egypt as far as Libya. Imperial Aramaic writing was so influential that it survived the collapse of the Persian Empire which had initially disseminated it, and continued to be used until the 2nd century AD. By the end of the 3rd century, variant forms of the script had diverged into distinct scripts such as Syriac, Nabataean and Palmyran. The form of Imperial Aramaic which changed the least is now used for writing the Hebrew language.
Imperial Aramaic was written from right to left, with or without spaces between words. The script was an abjad; each of the twenty-two letters represented a consonant. Because the interpretation of some words was ambiguous when the vowels were not written, Aramaic scribes began using a select few of the existing consonantal letters to indicate long vowels, first at the end of words, then inside words. Letters having this dual consonant/vowel function are (called matres lectionis). The letters waw and yudh could represent either the consonants [w] and [j] respectively, or the long vowels [u/o] and [i/e] respectively. Similarly, the letter aleph represented the consonant [ʔ] at the beginning of a word, or the long vowel [a/e] elsewhere. One script-specific punctuation mark is used in writing Imperial Aramaic, a section sign to mark topic divisions in texts.
Imperial Aramaic orthography was highly regular. Often the spellings of words more closely reflected their etymology than their pronunciation.