(The best full(er) history of Greek in English, from Mycenaean Greek to the modern day, is that of Geoffrey Horrocks, Greek: A History of the Language and its Speakers (1997). I have drawn upon it in writing this article.)

Although the Greek we learn is ancient Greek, Greek is a living language, and is the oldest living European language there is. Hittite is the oldest attested European language (c. 1700 BCE; Greek is the second oldest). Earlier hieroglyphic Cretan is the oldest writing found in Europe (c. 2000 BCE), but we do not know what language it is in – certainly not Greek. Even so, for centuries, in fact for more than a millennium, there was really no such thing as the Greek language (there was no Greek nation or state until modern times), as we can talk of the Latin language. Rather for most, if not all, of this time there was a number of Greek dialects, i.e. different regional forms of a language (the Greek dialects were mutually intelligible) – although some linguists do not distinguish between a dialect and a language and regard both as languages. Linguists also tell us that it is very difficult to say exactly what a language is. It was not until the form of Greek that we call the κοινή (the ‘common’ dialect: see below) became established that we can talk about the Greek language as anything resembling a single language.

The form of ancient Greek we learn is, for the most part, what is called ‘Classical’ Greek, a form of Greek that came to be used during what is called the ‘Classical’ period of Greek history, 479-323 BCE. One of the dialects used during this period is called ‘Attic’, and the Greek we learn is largely Classical, educated, literary (used for writing literature) Attic Greek. (Similarly, the Latin we learn is Classical, standard, elite, literary Latin used by educated people.) Alongside this ‘high’ register of written (and spoken) Attic there were also ‘lower’ registers of mainly spoken Attic used by the uneducated or under-educated majority of the population, snatches (no more than that) of which may be seen in Aristophanes. (Again, a parallel with Latin can be drawn.)

In the Classical period the Greek used by the writers of Classical literary Attic was probably broadly similar to the Greek they spoke. This would have been different from the varieties of the vernacular (the kind of language spoken by most of the people most of the time). Also, most of the people were illiterate – possibly as many as 95 per cent of the adult male population of Attica in the Classical period. From about 300 BCE, however, the Greek they spoke – a form of the κοινή – came to differ increasingly from written Classical literary Attic. Eventually it became so different that Classical literary Attic, which was preserved as a standard of correct Greek for belles lettres, had to be learned, by both native (as if a second language) and non-native (as a second language) speakers of Greek. In the Roman period Classical literary Attic was as different from contemporary spoken Greek, even of the educated classes, as Chaucer is from contemporary English. Grammar books, lexica, glossaries etc. were produced to help people to read and write literary Greek in Classical Attic. (A similar thing happened in the case of Latin.) Literary style and technique (as opposed to morphology and syntax – how much of this was actually taught and in what way in the Classical period is not clear) were learned from the Sophists and the later teachers of rhetoric.

It is called ‘Attic’ because it was the dialect of Greek that was used originally in that part of Greece known as Attica, of which Athens (the city and its environs) was to become the largest and most prominent community. I say ‘originally’ because it, or evolved forms of it, came to be first the principal, then, to all intents and purposes, the only, form of Greek used throughout the Greek-speaking world – and beyond – in antiquity. What is more, via the κοινή Attic became the foundation of Medieval and Modern Greek.

Although Attic Greek became so widespread and so dominant that, in the form of the κοινή it eventually supplanted all the other main dialects (as Latin did with the other Italic dialects and indigenous languages outside Italy), its beginnings were more humble and its pretensions less grandiose. As far as literature is concerned, Attic was a relatively late arrival on the scene (fifth century BCE), relative that is to two other dialects, Ionic and Aeolic, especially Ionic. The most admired and influential works of Greek literature, the Iliad and Odyssey of Homer, composed centuries before the beginning of the Classical period (in the eighth century BCE, probably), contain no authentically Homeric traces of Attic and are mainly in the Ionic dialect, the Eastern branch of which became, mainly because of its association with Homer, the most prestigious Greek literary dialect, embedding itself in and influencing every other literary dialect. And yet by about 300 BCE Ionic as a written dialect had largely disappeared, swallowed up by Attic, a not-too-distant relative, as it happens, of Ionic. How did this come about and how did Attic become so all-important?

It seems that Attic was originally very conservative and changed little, especially in its written form. However, from the second half of the sixth century BCE it came to be influenced increasingly by Ionic, mainly because of the prestige of the literature in Ionic. But as the power and prestige of Athens, and its literature, written in Attic, grew, Attic and Ionic steadily converged.

By about 300 BCE written Ionic had been more or less replaced by the form of ‘Ionicised’ Attic known as ‘Great Attic’. This was the form of Attic, used chiefly for commerce and administration, that evolved from Attic outside the confines of Attica in the wider Greek world and was the immediate forerunner of the κοινή, or a variety or varieties of the κοινή. Because Great Attic was used mainly for non-literary purposes, Classical literary Attic continued to be used for writing literature.

By the end of the fourth century BCE Great Attic had come to evolve into the ‘common dialect’ (ἡ κοινὴ διάλεκτος) used across the Greek world, where previously the traditional regional dialects had been used. A form/forms of the κοινή came to be used for literature as well as for more practical purposes. Eventually it replaced the other literary dialects and became almost the sole form of Greek for writing literature – Classical literary Attic continued to be learned, and used by some, alongside the κοινή, for writing literature.There were periodic artificial revivals of the use of the literary forms of the now largely defunct traditional dialects, for certain literary genres, e.g. Hellenistic poetry was written in Aeolic, Ionic and Doric. There were also attempts to reinstate Classical literary Attic, in place of the κοινή, as the sole form of Greek for literature, e.g. in the Atticism/Asianism conflicts of the third to first centuries BCE. The best known and most promising, if unsuccessful, attempt was made by writers of the second century CE cultural movement known as the ‘Second Sophistic’, writers such as Aelius Aristides and Lucian, who sought to bring back the language and style of writing of the age of the Sophists in the fifth century BCE.

In the third century CE a ‘toned down’ (Horrocks) form of Atticism, which was a hybrid of Classical literary Attic and the higher register(s) of the written κοινή, was adopted by most writers of literature. This remained the basis of all higher forms of writing for centuries, differentiating itself increasingly from the ordinary spoken κοινή used by most people. This distinction between a ‘higher’ or ‘purer’ form of mainly written, conservative ‘old style’ Greek used by an educated elite, and a ‘lower’ or ‘contaminated’ level of mainly spoken, ever changing, more ‘democratic’ (the word actually used is ‘demotic’) Greek used by the uneducated or under-educated majority, is known as ‘Diglossia’, a term invented in the 1950s. In Greece it became a fact of life, lasting for centuries and not being resolved until by political intervention well into the twentieth century.

So the κοινή became the standard written and spoken language of the educated classes, with periodic influences from Classical literary Attic for the register used for writing literature. Lower register varieties of the κοινή, spoken and written, were used by the less educated or the uneducated. The spoken κοινή was more heterogeneous than the written. In certain parts of the world – usually in the more rural and outlying – the indigenous, i.e. non-Greek languages, continued to be spoken for centuries, instead of the, κοινή or as well as the κοινή (and influencing it). Also, and again in the same kind of regions, the other traditional Greek dialects continued to be spoken, until they died out in late antiquity, leaving only varieties of an evolved κοινή, written and spoken, to be used by everybody.

Classical literary Attic, like standard, elite Latin, continued to be learned down the centuries, though sparsely and spasmodically only in Western Europe for most of the Middle Ages. It is, of course, still learned today, by the fortunate few.