Title: History of Greek
Content:  There are several theories about the origins of the Greek language. One theory suggests that it originated with a migration of proto-Greek speakers into the Greek peninsula, which is dated to any period between 3000 BC and 1700 BC. Another theory maintains that the migration into Greece occurred at a pre-proto-Greek (late PIE) stage, and the characteristic Greek sound-changes occurred later.
Title: Greece
Content:  The first textual evidence of the Greek language dates back to 15th century BC and the Linear B script which is associated with the Mycenaean Civilization. Greek was a widely spoken lingua franca in the Mediterranean world and beyond during Classical Antiquity, and would eventually become the official parlance of the Byzantine Empire. During the 19th and 20th centuries there was a major dispute known as the Greek language question, on whether the official language of Greece should be the archaic Katharevousa, created in the 19th century and used as the state and scholarly language, or the Dimotiki, the form of the 
Title: Greek language
Content:  For the Greek language used during particular eras, see Proto-Greek language, Mycenaean Greek, Ancient Greek, Koine Greek, Medieval Greek, and Modern Greek. Greek (Ελληνικά; ) is an independent branch of the Indo-European family of languages, native to Greece, Cyprus, Albania, and the other parts of the Balkans, the Black Sea coast, and the Eastern Mediterranean. It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet, which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary. The alphabet arose from the Phoenician script and 
Title: Proto-Greek language
Content:   The Proto-Greek language (also known as Proto-Hellenic) is the Indo-European language which was the last common ancestor of all varieties of Greek, including Mycenaean Greek, the subsequent ancient Greek dialects (i.e., Attic, Ionic, Aeolic, Doric, Arcadocypriot, and ancient Macedonian—either a dialect or a closely related Hellenic language) and, ultimately, Koine, Byzantine and Modern Greek (along with its variants). Proto-Greek speakers entered Greece sometime between 2200 and 1900 BCE,  with the diversification into a southern and a northern group beginning by approximately 1700 BCE.
Title: Greek literature
Content:  Ancient Greek literature refers to literature written in Ancient Greek dialects. These works range from the oldest surviving written works in the Greek language until works from the fifth century AD. The Greek language arose from the proto-Indo-European language; roughly two-thirds of its words can be derived from various reconstructions of the tongue. A number of alphabets and syllabaries had been used to render Greek, but surviving Greek literature was written in a Phoenician-derived alphabet that arose primarily in Greek Ionia and was fully adopted by Athens by the fifth century BC. 
Title: Greek language
Content:  in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems. The Greek language holds an important place in the history of the Western world. Beginning with the epics of Homer, ancient Greek literature includes many works of lasting importance in the European canon. Greek is also the language in which many of the foundational texts in science and philosophy were originally composed. The New Testament of the Christian Bible was also originally written in Greek. Together with the Latin texts and traditions of the Roman world, the Greek texts and Greek societies of antiquity constitute the objects of study of the discipline of Classics. During 
Title: Culture of Greece
Content:   The Greek language is the official language of the Hellenic Republic and Republic of Cyprus and has a total of 15 million speakers worldwide; it is an Indo-European language. It is particularly remarkable in the depth of its continuity, beginning with the pre-historic Mycenaean Greek and the Linear B script and maybe the Linear A script associated with Minoan civilization, though Linear A is still undeciphered. Greek language is clearly detected in the Mycenaean language and the Cypriot syllabary, and eventually the dialects of Ancient Greek, of which Attic Greek bears the most resemblance to Modern Greek. The history of the language spans over 3400 years of written records. Greek has had enormous impact on other languages both directly on the Romance languages, and indirectly through its influence on the emerging Latin language during the early days of Rome. Signs of this influence, and its many developments, can be seen throughout the family of Western European languages.
Title: Greeks
Content:  Most Greeks speak the Greek language, an independent branch of the Indo-European languages, with its closest relations possibly being Armenian (see Graeco-Armenian) or the Indo-Iranian languages (see Graeco-Aryan). It has the longest documented history of any living language and Greek literature has a continuous history of over 2,500 years. The oldest inscriptions in Greek are in the Linear B script, dated as far back as 1450 BC. Following the Greek Dark Ages, from which written records are absent, the Greek alphabet appears in the 9th–8th century BC. The Greek alphabet derived from the Phoenician alphabet, and in turn became the parent alphabet of the Latin, Cyrillic, and several other alphabets. The earliest Greek 
Title: Greek language
Content:  Modern Greek inherits most of its vocabulary from Ancient Greek, which in turn is an Indo-European language, but also includes a number of borrowings from the languages of the populations that inhabited Greece before the arrival of Proto-Greeks, some documented in Mycenaean texts; they include a large number of Greek toponyms. The form and meaning of many words have evolved. Loanwords (words of foreign origin) have entered the language, mainly from Latin, Venetian, and Turkish. During the older periods of Greek, loanwords into Greek acquired Greek inflections, thus leaving only a foreign root word. Modern borrowings (from the 20th century on), especially from French and English, are typically not inflected; other modern borrowings are derived from South Slavic (Macedonian/Bulgarian) and Eastern Romance languages (Aromanian and Megleno-Romanian).
Title: Greeks
Content:  works are the Homeric epics, variously dated from the 8th to the 6th century BC. Notable scientific and mathematical works include Euclid's Elements, Ptolemy's Almagest, and others. The New Testament was originally written in Koine Greek. Greek demonstrates several linguistic features that are shared with other Balkan languages, such as Albanian, Bulgarian and Eastern Romance languages (see Balkan sprachbund), and has absorbed many foreign words, primarily of Western European and Turkish origin. Because of the movements of Philhellenism and the Diafotismos in the 19th century, which emphasized the modern Greeks' ancient heritage, these foreign influences were excluded from official use via the creation of Katharevousa, a somewhat artificial form of Greek purged of 

Question: where does greek language come from?
Answer: Indo-European languages.