As promised, here's a relevant bit from the introduction to Peter Mackridge's The Modern Greek Language (1985). Now this should cover some of the historical background. I'll look for a short morphological and/or syntactical analysis later on.
THE GREEK LANGUAGE QUESTION
Diglossia (the contemporaneous existence of two different varieties of the same language used for different purposes) has been a feature of the Greek language since the end of the fourth century BC, when the spoken language began to diverge perceptibly from the old norms which were being adhered to by writers. The situation in which at least some writers use a variety of the language which differs markedly from the spoken has continued until the present day. This does not mean that the written language has remained the same from a certain date onwards: on the contrary, despite intermittent reactions during which authors have attempted to return to the alleged purity of Attic or Hellenistic Greek, the written language has developed through a fairly constant process of compromise with the spoken. Meanwhile the spoken language (at least until the nineteenth century) has continued along its own path, undergoing developments which are partly potentialities within the Greek language itself and partly the result of influence from other languages (particularly Latin, Italian and Turkish).
Between Hellenistic and modern times there were fairly well-defined areas within which each variety of the language functioned, even though there was no official codification involved. Thus for most of the Byzantine period the spoken language was tacitly excluded from writing. But the boundaries between the areas in which the different varieties were used were subject to alteration, and in the late Byzantine period it became acceptable for certain types of secular verse (chiefly romances) to be composed in the spoken language. With the end of the Byzantine Empire rather more areas of writing were opened up to the spoken language, although it tended to be confined (apart from belles-lettres) to works deliberately intended for a popular audience.
Until the eighteenth century, then, because of a general agreement about which variety of language was suitable for each type of use, there was no overt language question in Greece. The controversy really began in the late eighteenth century, when, under the influence of the French Enlightenment, Greek intellectuals began to publish significant numbers of secular works of an educational nature, in an effort to revive the arts and sciences which they perceived as being sadly lacking in Greece. In so doing they were (some consciously, others unconsciously) preparing the ground for the political independence of Greece. Some of these scholars believed that a Greek cultural rebirth was possible only through a return to Ancient Greek language and culture: they saw it as a prerequisite for this rebirth that the Greek people should learn not only to read but also to write and speak Ancient Greek, to such an extent that AG would actually supersede the ‘vulgar’ and ‘debased’ language spoken by their countrymen. Others felt that the Greek people could be enlightened only through the use of the spoken language in serious writing. (At that time spoken Greek was usually known as ρωμαίικα ‘Romaic’, as opposed to ελληνικά ‘Greek’, which referred to the ancient language; by 1821 however ελληνικά was being used for both languages, a fact which has been the source of some confusion.) But these two groups were by no means the largest: the majority of the Greek Enlighteners (the most influential of these being A. Korais) preferred to use a variety of language which, while largely based on the structure of the spoken language, contained a large number of elements from Classical and Hellenistic Greek, but also (although its proponents never admitted this) owed much to French turns of phrase. Each of these groups the archaists (or Atticists), the vulgarists, and the compromisers set about defending their own chosen variety of the language and attacking those who supported any other variety, in a host of polemical books and articles.
The terms δημοτική (demotic, ‘the people’s language’) and καθαρεύουσα (katharevousa, ‘the purifying language’) were hardly used at this time (i.e. the half-century leading up to the Greek War of Independence of 1821), even though the latter was first used in 1796 and the former in 1818, as far as I can ascertain: they became current in the late nineteenth century. Nevertheless, the variety of language supported by the compromisers became what we know as katharevousa. This is not to say that Korais and his like-minded intellectuals actually invented katharevousa: the variety of Greek which they proposed as the language of the state and of education already existed, but more as a result of haphazard juxtapositions of ancient and modern elements than as a methodically planned compromise.
The establishment of the Greek state (c. 1830) saw the institutionalization of katharevousa as the language of all governmental and administrative business, education, and the press. All other writing outside poetry also came to use katharevousa, while poets were divided: some wrote entirely in demotic, others entirely in katharevousa, and yet others sometimes in one variety and sometimes in the other. The official language gradually moved further away from the spoken between 1830 and 1880, as intellectual leaders called for increasingly more ‘purification’, which meant the arbitrary imposition of archaic features on to what was still a basically modern structure, without any attempt to assimilate these features to the essential rules of the modem language. By the 1850s, the gradual move towards a more archaic language was generally seen as ‘progressive’, the language of Korais being viewed as ‘old-fashioned’.
As Mirambel (1964: 415) points out, rather than rejuvenating old words, katharevousa ‘vieillit des mots neufs’ by adding ancient inflexions and other features to neologisms. A good example is μπόμπα (bomba) 'bomb’, which became (and has remained) βόμβα (vomva) for two reasons: (a) initial μπ did not occur in Ancient Greek; and (b) Western European b was in any case transliterated into katharevousa as β (pronounced v) because Ancient Greek β (pronounced b) was transliterated into Western European languages as b! The advocates of katharevousa, blinding themselves to sound changes which had taken place since Classical times, ignored the fact that the sequence mv was non-existent not only in words of demotic origin, but in Classical Greek too (Classical μβ was pronounced mb, as in Modern Greek μπ). The result is that this loanword was dressed up to look like an ancient word, while each letter was given its modern pronunciation, irrespective of the fact that this gave rise to a sequence of sounds which had been excluded, by natural processes, from the language.
The fact is, however, that spoken Greek is so close to Ancient Greek that the temptation to bridge the small gap which separated them was widespread. But, as Mirambel (1964: 417) points out, whereas the Hellenistic purists wrote in a particular dialect which had been alive at a particular time (viz. Classical Attic), the modern purists tended to accept any elements of post-Homeric Greek that did not smack of demotic.
During this period (1830-80) the language question was more or less dormant. The reaction against the increasing archaism of katharevousa came first from the poets, who saw the impossibility of writing true poetry in such an artificial language and then from the literary prose-writers and dramatists (in the 1880s and 1890s), who in their turn realized that they could not write stories and plays about everyday Greek life when most of the vocabulary associated with that life was excluded from writing. The conversion of Greek prose fiction and drama from katharevousa to demotic occurred with great rapidity. Having won literature over to their side, the demoticists went on, especially from the first decade of the twentieth century onwards, to demand that katharevousa be abolished altogether. Reaction against the threat of domination by demotic (often known as μαλλιαρή, or ‘hairy language’ since its proponents were reputed to have long hair) sometimes took a violent form. Riots broke out in Athens in 1901, when A. Pallis published his demotic translation of the New Testament and again in 1903, when the National Theatre put on a performance of Aeschylus in a semi-demotic translation. In view of these incidents, and particularly because of the demoticists’ insistence that demotic should become the official medium of education, a clause was included for the first time in the Constitution of 1911 declaring katharevousa to be the official language of the state and making it a punishable offence to attempt to alter this situation.
Despite this, demotic texts were introduced for the first time into primary-school readers in 1913, chiefly as a result of pressure from a demoticist lobby known as the Educational Society, founded in 1910, and demotic became the chief language of primary education between 1917 and 1920. But for some years thereafter, the situation was fluid, with successive governments increasing or decreasing the use of demotic in primary schools. For the most part, secondary schools and the University of Athens remained unaffected by demoticism: indeed, no Modern Greek of any sort, not even katharevousa was taught in secondary schools until 1909; before this there was a total official disregard for Modem Greek culture. By this time, the language question had become an overtly political issue. Already, in the first decade of the century, demoticists were accused of involvement in a Russian plot to take over Greece, and the Russian Revolution only served to make such accusations all the more emotive. The proponents of both katharevousa and demotic now used the term ‘national language’ to refer to their own variety of Greek, accusing their opponents of attempting to jeopardize the unity of the: nation. The controversy reached such a level of fanaticism that in 1941, during the Axis Occupation, a distinguished Classical scholar was dismissed from his teaching post at Athens University for publishing an article printed according to the ‘single-accent system’.
Also in 1941, however, the cause of demotic made an historic step forward with the publication of the Modern Greek Grammar by Triandaphyllidis and others (Triandaphyllidis was one of the founder members of the Educational Society). The authors had been commissioned to write the grammar by the dictator Metaxas, who foresaw its use as an official grammar of demotic. Although the Axis Occupation meant that the grammar had considerably less impact than it should have done, it is nevertheless looked to as a more or less authoritative guide to morphology (it does not deal with syntax).
In 1964 the ruling Centre Union Party put demotic on an equal footing with katharevousa: as the language of education. But this reform was short-lived, since the military dictatorship of 1967-74 confined the teaching of demotic to the first four grades of primary school. One of the beneficial consequences of the military regime was the anti-katharevousa reaction that followed it. Law 309 of 1976 instituted Νεοελληνική (Δημοτική) as the language not only of education but of the administration while the 1975 Constitution sensibly made no mention of an ‘official language’. The determination of the government of the time that Greece should join the EEC perhaps helped to expedite the process of demoticization. Efforts were made to train civil servants in the use of demotic, but naturally the process has been a gradual one, many bureaucrats being slow to come to terms with the change.
After the electoral victory of the PASOK party in 1981, moves were made to introduce the monotonic system not only into schools, but into he administration. For schoolchildren this was generally felt to result in great saving of time: it had been estimated that out of the 12,000 hours which the average child spent on grammar during twelve years’ schooling, 3,000 were spent on learning how to use the accents and breathings.
STANDARD MODERN GREEK
Since 1976 Modern Greek diglossia has more or less ceased to exist, and there is for most purposes a single, unified Greek language. In Standard Modern Greek the Greek language has come closer to developing a set of universally accepted norms than at any other stage in its history.