Greek is an Indo-European language, primarily spoken in Greece and Cyprus. It is one of the few continuously written languages since antiquity, though the modern form differs significantly from the classical dialect. It dates as a written language from 800 BC, and was the language of the poet Homer. It is written with the Greek alphabet.
Homeric Greek is an early literary language, a form of Attic-Ionic. Archaic Greek followed Homeric, and culminated in Classical Greek with Plato, Aristotle, and the plays of Euripides, Aeschylus, Sophocles,and Aristophanes.
The Greek spread by Alexander the Great was also literary. By the 1st century AD, it had evolved into Koine Greek ("common" Greek), which is comparable to Vulgar Latin. Koine Greek and Vulgar Latin had phonological changes and simplifications in grammar and syntax that differed from Classical Greek and Classical Latin. This was the Greek in use in Palestine at the time of Jesus and was the language of the New Testament. Greek was the common trade language of the Roman Empire.
Some centuries before, the Jews of Alexandria rendered a version of the Old Testament into Greek, the Septuagint (LXX), ("the seventy" or "seventy-two" based on the number of translators). This version of the Old Testament differs from that used by most Protestants, who use the Masoretic Hebrew text, but continues to be used by the Catholic Church (in Latin) and by the Greek Orthodox (untranslated).
In the Attic Greek language, verbs are conjugated for three moods and three voices; the three moods being the indicative, subjunctive and optative, and the three voices being the active, passive and middle. Greek syntax and linguistic structure is similar to Latin, with several words sharing links with one another (for example, the word "pater"). Ancient Greek is notorious for having a large proportion of irregular verbs; the scholar L. A. Wilding has calculated that most verbs show some degree of inconsistency.