When I first began to think that poetry is an art of memory, I started putting the thought into practice, by composing and retaining verses in memory without the use of writing. I started with gnomic poems, short and compressed, but heavily ornamented and full of imagery. I soon found that such verses, planted in the mind and constantly revisited, were able to root and grow and flower into forms that would never have occurred to me had they been pressed onto the page.
Emboldened, I decided to transpose the technique to longer poems and traditional material. I started working through the Electronic Beowulf, producing a loose translation of the Old English poem that conformed to the original meter, and encoding each verse in memory without ever writing it down.1 This was by no means beyond my powers, and at one point I was able to recite around two-thirds of the translated poem in this way. But while the composition of gnomic verses had sometimes risen to the level of a spiritual exercise, this attempt to memorize a traditional epic felt more like an exercise in low drudgery.
What had misled me into it was the stereotype of the bard – the vague, attenuated collective memory of traditional poetry that exists in the modern mind. The preliterate poet, I thought, twanged his harp and remembered the verses that had been handed down by his ancestors and faithfully recited them from memory.
And so I persisted in my ignorance, and in my drudgery – until I happened to read The Singer of Tales by Albert Lord. This book is a must-read for anyone who wants to understand traditional poetry for real. It narrates the rediscovery of the art, almost at the moment of its death, by modern men – and reveals it to have been something much more interesting and creative, but also much more difficult, than the mere regurgitation of verses from memory.
The Oral Theory
The story begins with Lord’s teacher, the American classicist Milman Parry, who published two French-language doctoral dissertations on Homer in the 1920s. The focus of Parry’s study was the repeated use of certain epithets and phrases in the Homeric poems – ‘swift-foot Achilles’, ‘many-witted Odysseus’, ‘winged words’, ‘rosy-fingered dawn’, and so on. All of these and more are examples of the poetic formula – defined by Parry as “a group of words which is regularly employed under the same metrical conditions to express a given essential idea”.2
Parry argued that Homer’s deployment of formulas in verses was dictated not by aesthetics or meaning, but simply by the practical need to fill out open parts of the Greek hexameter line with metrically appropriate material. This, after so many rationalizations of Homer’s artistic choices by pious classicists, was something of a demythologizing approach – hence Parry’s nickname, the ‘Darwin of the Homerists’. Yet this Darwinism would seem to explain why the Iliad describes Achilles as “swift-footed” when he is sitting down in his camp, why the Homeric Hymns describe Hermes as “slayer of Argus” when he is still a newborn baby, etc.
But why did Homer need such a technique to construct hexameters, when later poets like Apollonius and Virgil could do without it? Parry’s answer is that Homer composed his verses, not by writing them out at leisure, but by extemporizing them in the moment of oral performance. For this he had to resort to a common stock of poetic formulas, handed down to him by a long line of traditional poets stretching into the distant past.
In Parry’s own words (from “Studies in the Epic Technique of Oral Verse-Making: I. Homer and Homeric Style”; emphasis mine):
The oral poet expresses only ideas for which he has a fixed means of expression. He is by no means the servant of his diction: he can put his phrases together in an endless number of ways; but still they set bounds and forbid him the search of a style which would be altogether his own. For the style which he uses is not his at all: it is the creation of a long line of poets or even of an entire people. No one man could get together any but the smallest part of the diction which is needed for making verses orally, and which is made of a really vast number of word-groups each of which serves two ends: it expresses a given idea in fitting terms and fills just the space in the verse which allows it to be joined to the phrases which go before and after and which, with it, make the sentence. As one poet finds a phrase which is both pleasing and easily used, the group takes it up, and its survival is a further proving of these two prime qualities. It is the sum of single phrases thus found, tried, and kept which makes up the diction.
Because the traditional poet has neither the luxury nor the need to vary them for the sake of variation, these formulas tend to be repeated much more often than the phrases of literary poets. This Parry goes on to demonstrate, by distinguishing the practical formula from the phrase merely repeated for literary effect, and analysing the density of formulas in the first twenty-five lines of the Iliad and Odyssey.
As Lord warns us in his introduction to Singer of Tales (p.5), we must carefully distinguish this technique from improvization on the one hand and memorization on the other. Traditional composition – what we might call, in a special sense of the word, recomposition – combines elements of both.
This is why it is better to speak of traditional poetry than ‘oral poetry’, which is a much wider and blurrier concept. Many ‘oral poets’ throughout history have been nothing but reciters of memorized verses: one example would be the rhapsodes of ancient Greece, who recited the works of Homer and Hesiod, and another would be the jongleurs of medieval Europe. But theirs was a later, lesser art than that of the ‘singers’ (Greek aoidoi) and ‘shapers’ (Old English scopas) who practiced the art of recomposition, and seem to have been granted more social respect for it.
An ‘oral poet’ might also be a spontaneous improvizer – and while the Italian improvisatori may furnish us with one example of this technique, who needs them when we can simply point to modern freestyle rappers? Such improvization is probably even more demanding than recomposition; but it is also shallower, more unreliable, and more difficult to sustain beyond a few minutes. That is why rap, while fully deserving of the name of oral poetry, is not traditional poetry and is better suited to flyting than serious narrative.
The South Slavic Tradition
Speculation had gone on for centuries as to whether the Iliad and Odyssey were the work of one or many authors, whether they were worked from one story or many, etc. The ‘oral theory’ had the potential to slice through this Gordian knot, by showing how a single poet might have composed these works from a body of inherited material.
All Parry had to do was to back the theory up with a living example of traditional composition. This he would find in the early 1930s, in the course of two field trips to what was then Jugoslavia, spent touring remote rural areas where one might still hear a form of poetry that had passed away everywhere else in Europe. Lord accompanied him as his student and assistant – and after Parry’s untimely death, he wrote up the findings and the theory in Singer of Tales, which appeared in 1960 and put the oral theory as it were ‘on the map’.
Parry and Lord ended up recording and transcribing thousands of South Slavic song-poems, the vast majority of which have never been translated from the Serbo-Croatian language.3 Almost all of the singers were illiterate, and they composed much as Parry had theorized, employing formulaic phrases handed down by the tradition or improvized by analogy with existing models. No given poem was ever sung quite the same way twice (one method for proving this was to stop the singer early on, on the pretence that the recording equipment was faulty, and ask him to start again from the beginning). And the best singers, such as the virtuoso Avdo Međedović, were able to stretch out their songs to a total line-count comparable to that of the Iliad and Odyssey.
Of course, the traditional poetry of the South Slavs was in many ways different from that of the ancient Greeks. Instead of the lyre of antiquity, the ubiquitous instrument was the fiddle-like gusle, with which the singers kept up a constant melodic accompaniment to the songs. The common meter for epic poetry was not the hexameter, but a shorter ten-syllable line called the deseterac, consisting of four initial syllables followed by a caesura and six more syllables. The short example below comes from Singer of Tales (pp.60-1); I have added slashes to the original text to highlight the caesuras, and converted the translation into a more consistent English style:
Beg se spremi / na bijelu kulu, | The beg gets prepared / in his white tower, A pripasa / silah i oružje, | He girds on / his belt and arms, I opremi / široka dorata. | And he equips / his broad brown horse. Navali mu / pusat i saltanet, | He puts upon him / his arms and trappings, Jalah reče / posede hajvana, | With a "By Allah" / he mounts his beast, Pa ga nagna / preko polja ravna. | And drives him forth / across the level plain. Oh zečki je / polje pregazio, | Like a rabbit / he runs across the plain, A vučki se / maši planinama, | Like a wolf / he sties upon the mountains, Preturijo / dvije tri planine… | Passing on his way / two or three mountains...
As Lord shows, of these formulas recur in other poems from the same tradition, though not necessarily at the level of word-for-word repetition. For example, the initial half-line Jalah reče (‘with a “By Allah”’) appears often in the first half of the line, invariably paired with a closing half-line describing the mounting of a horse at the outset of a journey. Certain lines or couplets, like the one about rabbits and wolves, also lend themselves to relative stability of form. But the higher determining factor is the recurrence of essential ideas – the ‘themes’ and ‘type-scenes’, such as the arming of a hero or his escape from a prison, which are reused time and again across the tradition in different forms and different phrasal clothing.
It would be wrong to get the idea that this is a kind of mosaic-arrangement with themes and formulas. As Lord explains (ibid, p.37), the traditional poetic diction works more like a “special grammar”, constrained by the meter and characterized by an archaizing style. Formulaic half-lines, lines and clusters of lines are the “phrases and clauses and sentences of this specialized poetic grammar”, and he who has learned to speak this language-upon-a-language fluently “does not move any more mechanically within it than we do in ordinary speech.”
When we speak a language, our native language, we do not repeat words and phrases that we have memorized consciously, but the words and sentences emerge from habitual usage. This is true of the singer of tales working in his specialized grammar. He does not "memorize" formulas, any more than we as children "memorize" language. He learns them by hearing them in other singers' songs, and by habitual usage they become part of his singing as well. Memorization is a conscious act of making one's own, and repeating, something that one regards as fixed and not one's own. The learning of an oral poetic language follows the same principles as the learning of language itself, not by the conscious schematization of elementary grammars but by the natural oral method.
Habituation to writing and reading tends to destroy this poetic language – not because it renders it unnecessary, or shows it up as primitive and repetitive, but because it introduces the idea of fixed texts that must be reproduced mechanically without individual deviations. Nothing would be more mistaken than to assume that traditional poetry dies out because a people comes to despise it. More often, it dies from the adoration of its perfected exemplars, preserved in a charmed crystalline stasis while the living tradition about them goes to the dogs.
We might visualize the conversion of an orally-habituated people to literacy as the advance of a glacier upon a wood: a vast destruction of cultural life, which nonetheless preserves a number of specimens in death, and eventually gives rise to different forms of life that are better adapted to the new environment. One of these is the phenomenon of jongleurism, or memorized recital disguised as traditional poetry, which allows the fixed text to establish its dominion even in the minds of illiterates.
By the time Lord wrapped up his fieldwork and wrote his book, the South Slavic tradition was already degenerating into jongleurism. On one side, the tradition was eaten at by the advance of literacy, and the fading of the heroic values that it described; on the other, it was parasitized by nationalist pseudo-traditionalism, and the veneration of songbooks such as those compiled by Vuk Karadžić. Today, it would seem, the song and gusle remain, but the technique of recomposition has vanished.
Lord has harsh words for such jongleurs (ibid, p.147):
Those singers who accept the idea of a fixed text are lost to oral traditional processes. This means death to oral tradition and the rise of a generation of "singers" who are reproducers rather than re-creators. Such are the men who appear in costume at folk festivals and sing the songs they have memorized from Vuk's collection. You or I could do the same with a certain amount of training and with a costume. These "singers" are really counterfeits masquerading as epic bards! They borrow the songs of real singers complete from first word to last; one can follow the text in the book. They are a menace to the collector.
Once I had read these words, I could give up my attempt to memorize Beowulf with a clear conscience. It had felt to me like low drudgery because that it is exactly what it was.4 And yet the true art of traditional composition is not only higher, but also much harder – and, one would be forgiven for thinking, beyond the reach of literates who no longer have access to a functioning poetic language.
That is precisely the verdict of Lord (ibid, p.138) – “Once the oral technique is lost, it is never regained.” And I suppose that it would be echoed by most, if not all, other scholars in the field of oral tradition; at the very least, I have never yet seen it contradicted. But it cannot be the last word for someone who has dedicated a blog to the restoration of traditional poetry. On what basis do I, with less expertise than the least of the scholars, dare to say that opinion is divided on the subject?
Skirmishes on the Border
Let’s start by looking at that last quotation from Singer of Tales in context:
It is worthy of emphasis that the question we have asked ourselves is whether there can be such a thing as a transitional text; not a period of transition between oral and written style, or between illiteracy and literacy, but a text, product of the creative brain of a single individual. When this emphasis is clear, it becomes possible to turn the question into whether there can be a single individual who in composing an epic would think now in one way and now in another, or, perhaps, in a manner that is a combination of two techniques. I believe that the answer must be in the negative, because the two techniques are, I submit, contradictory and mutually exclusive. Once the oral technique is lost, it is never regained. [emphasis added] The written technique, on the other hand, is not compatible with the oral technique, and the two could not possibly combine, to form another, a third, a "transitional" technique.
What Lord is saying here is that there is no such thing as a written poem that stands midway between oral and literate compositional styles – unless it be a transcription of a sung performance by an oral poet, or a spoken dictation by such a poet, or at most a written transcription by an oral poet who has “learned just enough writing to put down laboriously a song that he would ordinarily sing”. So if a written poem seems to show evidence of oral-traditional composition, such as high formula density – and other telltale marks, such as type-scenes – then we must classify it as either a transcript of an oral poem, such as those Parry collected from Avdo, or a literary poem that imitates oral style in the manner of Virgil’s Aeneid.
It just so happens that this argument turned out to be an Achilles’ Heel for the oral theory – a weak front on which critics could launch counterattacks as the theory swept across the academic landscape. In later works – Epic Singers and Oral Tradition, and the posthumously-published Singer Resumes the Tale – Lord has partly recanted and taken up a more defensible position, by admitting that the forms of oral composition can live on temporarily in the new medium of literary poetry.5 By this time, considerable damage had been done by the excesses of others.
One of the most obvious applications of oral theory is to the study of Old English poetry written down in the Anglo-Saxon period. Beowulf certainly rings like a traditional tale, and is full of formulaic repetitions – half-lines like goldwine gumena (gold-friend of men, used of a king), duguþ ond geogoþ (veterans and youths), etc., and full lines like Beowulf maþelode / bearn Ecgþeow (Beowulf spoke / son of Edgethew). Not only the meter but also many of the formulas are shared by other poems from the same period, suggesting a common word-hoard of traditional diction such as that of the South Slavs. So the Old English scholar Francis Magoun, in the early 1950s, marched in to annex this territory with an article entitled “Oral-Formulaic Character of Anglo-Saxon Narrative Poetry”.
Alas, the theory met with an unexpected reverse. Magoun, imitating Parry, had established the ‘oral’ character of Beowulf by sampling twenty-five lines and counting the formulas – but as it turns out, the same test also throws up a positive result for the Alliterative Morte Arthure, a much later poem in Middle English that makes explicit reference to literary sources. And while Magoun noted the presence of formulas in poems based on Biblical material, he simply assumed that these stories had passed into the oral tradition of the ‘singers’. But as Larry Benson showed in his counter-argument, “The Literary Character of Anglo-Saxon Formulaic Poetry”, Old English translations of Latin works such as The Phoenix and The Meters of Boethius are no less filled with traditional formulas.6 The existence of ‘transitional texts’ could no longer be denied; and this presented a problem for the oral theory, given that everything we know for sure about premodern oral traditions comes from written texts.
Some critics would carry the pushback on this front as far as Parry’s early work on Homer. In Naming Achilles, David Shive analysed all the formulas used in the Iliad for the essential idea of ‘Achilles’, and concluded that there is “less economy…but more extension” (p.16) in Homer’s language than Parry had found in his less detailed analysis. That is to say, according to Shive7, the Iliad is less like an oral poem and more like a literary poem than Parry had thought. If even Homer’s works could be claimed as ‘transitional texts’, then the only secure ground for the oral theory would be the hinterlands of South Slavic epic and other late-surviving oral traditions.
To be clear, as far as I am concerned, the body of fact assembled by Parry and Lord would be unassailable even if Homer were proven beyond doubt to have wielded the pen. We know from the South Slavic evidence how epic poetry was composed without the aid of writing; we know that this style resembles that of the earliest poets in societies not long converted to literacy; and we know that later literary poetry shows a divergence from that style (sometimes obscured by imitation). The conclusions are obvious; and as for questions of whether and to what extent which work falls into one or the other category, I do not much care how scholars choose to split the difference.
But the fact that the oral theory got bogged down in debate, instead of merely sweeping literary criticism into the dustbin of history, had a salutary effect upon it. It served to teach the oral theorists that the dividing line between oral and literary poetry is much less clear than it was initially thought to be. At the end of this learning process, John Miles Foley (in Homer’s Traditional Art, p.xiii) could write that “scholars and fieldworkers generally concur that the supposed ‘Great Divide’ of orality versus literacy does not exist.”
But this admission presents an opening – apparently never glimpsed by the oral theorists – to those of us who would overturn Lord’s verdict on the impossibility of regaining the ‘oral technique’. Literacy, as we have seen, was not an instant kiss of death to that technique; rather, it asphyxiated gradually under the idea of the fixed text and the new mental habits inculcated by writing. The natural corollary of this is that the conscious rejection of textual fixity, and the reintroduction of oral practices like sung performance, might restore technique and tradition to life. This would not be a recreation from scratch, but a rebirth from the salvaged seed of the very poems that have been preserved for us in textual cryogenic stasis.
This is not a proposition to be haggled over in theory, but one to be gambled upon in practice. Given that traditional poetic diction is a species of language, the model for the restorationist project would be the conlang (like Elvish) or the revived language (like modern Cornish). It would have to 1) begin with a vast commitment to re-translate the texts of traditional poems into a single modern English meter – comparable to the Greek hexameter, South Slavic deseterac, or Anglo-Saxon meter – and subsequently 2) proceed to subject this material to the crucible of reintroduced oral practices, primarily the art of recomposition.
We may have no doubt that the most felicitous result of such a project would not be a ‘pure’ oral style, but a ‘transitional’ one that coexists with literacy. And yet, while all such styles hitherto have represented the decay of an existing tradition, this one would present a movement in the opposite direction. For better or worse, it would be a transitional style of a type never seen before.
In Defence of Traditional Poetry
I have suggested that this could be a formative project for the dissident ‘art-right’, which has yet to find a truly distinctive style. But even a sympathizer must be thinking at this point that it sounds like a lot of hard work, all for the sake of reviving a form of poetry that defies modern artistic sensibilities by embracing tropes and clichés. Should traditional poetry be restored? Or is it not deservedly obsolete? After all, every independent free thinker with a mind full of original ideas agrees that clichés are the worst thing ever.
Admittedly, whatever the intentions of Parry, Lord, and other oral theorists, the reader tends to come away from their work with a rather disparaging view of the traditional poetic art. It comes across as mechanical and collectivistic, constrained at every turn, something from which the written word has mercifully liberated us. But this is a misconception, analogous to the distorted idea of ancient languages that one tends to get by looking at dictionaries and declension charts. Foley, in his introduction to Homer’s Traditional Art (p.7), has this to say by way of correction:
“For the sake of art, not for the sake of meter” speaks most directly to the formulaic diction so typical of Homeric epic, which appears to be shaped primarily according to the demands of the hexameter – metri causa is the usual term. If this is so, some have asked, then how can we ascribe poetic excellence to Homer? Could he exercise any choice in naming people and gods in his epics, for example, or was he simply a prisoner of his inherited diction, forced into compliance by the tyranny of a prefabricated language? This proverb contends that meaning and art come first, that stock expressions like the recurrent names for people and gods have resonance not as original creations or situation-specific usages but as traditional signs. The signs themselves may be metrically governed, but their implications are not.
Foley goes on to introduce the concept of traditional referentiality – the depth of meaning that resonates through formulas, as well as wider themes and story-patterns, as a result of all their previous uses in the context of a poetic tradition. Needless to say, this aspect of traditional diction is apt to go unnoticed by the uninitiated, who are left with a false impression of mind-numbing repetition. An example from the South Slavic tradition (ibid, p.19) suffices to illustrate:
Ubiquitous throughout the Moslem songs, "San usnila, pa se prepanula" ("You've dreamed a dream, so you're frightened") regularly occurs as a response to a report of a battle about to begin or some other dire event on the near horizon, and is customarily spoken by someone apparently in charge to the supposedly less qualified reporter. Its proverbial nature marks a gently chiding, somewhat patronizing attitude on the part of the person who seeks to dismiss the threat as merely a dream and therefore not to be taken seriously. The proverbial meaning of this South Slavic sêma [sign], however, mandates something that cannot be predicted without the immanent contribution of the poetic tradition: to wit, the "dream" will soon become a reality, and ignoring its warning will cost many lives.
Traditional referentiality is what makes a poetic language antithetical to Orwell’s Newspeak, or Sonja Lang’s Toki Pona, in which everything is stripped down to a basely communicative babytalk. It is not so alien to those of us who have studied the Chinese language, which is enriched by many thousands of traditional idioms quoted or paraphrased from old poetry and literature. It can be summoned up on an occasional basis even in modern English – for example, one cannot speak of the sea as a ‘whale-road’ without evoking the Western Dark Ages, or talk of ‘incarnadining’ it without conjuring up a more fine-tuned web of associations.
But to the extent that English still partakes of this higher and narrower form of meaning, it is only in spite of the permanent revolutionary campaign to subvert ‘tropes’ and liquidate ‘clichés’. Even as it substitutes a kaleidoscope of novelty for stable traditional referentiality, this campaign never actually succeeds in annihilating its targets. Thrown out of doors, they continually fly back in through the window – partly because there is nothing new under the sun, partly because subversion is just another multiform of a trope, but mostly because the repetitions of tradition have been replaced wholesale by those of propaganda.
A functioning traditional art form, still rooted in a practical craft, takes a different attitude to originality. In Singer of Tales, Lord mentions that Avdo Međedović frequently departed from traditional forms of expression – having “thought in poetic form all his life”, he had “sufficient mastery of that form to not only be able to fit his thought into it but also to break it at will” (p.140). But that is the hard-earned prerogative of the master and genius who stand upon the forms of an art. Those who stand below them, the neophyte and journeyman, will never attain basic competence if they are instead persuaded to simulate masterly licence.8
In sum, permanent revolution in art produces much the same destruction, usurpation and charlatanry as does permanent revolution in society, and those of us who despise it in the one sphere ought not to submit to it unthinkingly in the other.
But this, of course, is very far from being a comprehensive defence of traditional poetry. There is a lot more to this long-forgotten art than its diction and mechanics, and I hope to unfold a fuller picture in later posts.
I hasten to confess that I sometimes cheated by recording verses on a smartphone, and then immediately consigning the files to the deletion bin, giving me thirty days before automatic deletion to make sure I had got them by heart.
Although some accounts of Parry’s work give the impression that he discovered formulas and oral-composition by himself, the Wikipedia article on the oral theory correctly notes that he built upon the observations of those who treated the subject before him.
The original material is available at the Milman Parry Collection of Oral Literature; those texts that were translated were released in a series called Serbocroatian Heroic Songs, now out of print but sporadically available from online sellers. These volumes are in pairs, some containing only Serbo-Croatian originals, and others only English translations. Although one is apt to be fooled by the early publication of a volume 14, the vast majority of the translations were in fact never published and presumably never completed.
To clarify, I am disparaging only the memorized recital of long narrative epics, not the memorization of shorter lyric songs, gnomic poems, etc. etc.
Lord’s original position on transitional texts defies common sense, but I suspect that he was provoked into it by the snobbery of classical scholars who did not want their bard associated with illiterate Illyrian rustics. In Singer of Tales (p.138) he has this to say of them:
Diplomatic Homerists would like to find refuge in a transitional poet who is both an oral poet – they cannot disprove the evidence of his style – and a written poet – they cannot, on the other hand, tolerate the unwashed illiterate.
However much Lord may have wished to deny it to them, they did in the end manage to claw back this ‘refuge’ from the oral theory.
In the Preface to Daemon in the Wood (p.3-13), David Bynum excoriated Magoun, Benson and others for applying Parry’s theory in a simplistic and mechanical way. He points out that Parry had never equated the formula with a mere repetition, but rather defined it as “a group of words which is regularly employed under the same metrical conditions to express a given essential idea”, and distinguished between the use of formulas for practical reasons and the repetition of phrases for literary effect. While all of this is true, Parry did say that it is more easy to discern the use of formulas in the case of repetitions; and moreover, if Magoun had not understood Parry’s theory then Lord had not understood it either, to judge from his approving comments on Magoun’s analysis of Beowulf in Singer of Tales (p.211-2).
Although I have read Shive’s book and followed his argument carefully, I do not have the requisite Ancient Greek game to evaluate his data to my own satisfaction. See here for a dismissive riposte by a major oral-traditional scholar.
Of course, the corollary of this argument is that the new traditional poetry must start with neophytes and journeymen before it ends up with masters. This, I think, must be accepted – for there is no way to master an art that has not yet been restored, and it is equally impossible to restore an art without practicing it. Let us have the patience to tend the tree, while others gather the flowers; let us have the wisdom to hammer upon the sword, while others make fancier moves with sticks.
if musical styles are somewhat of a guide, I think there may be a mistake in discounting memorization. We find that you always start by memorizing -- this happens because some phrasing isn't as easy to get correct, so you memorize that. But then what happens is, like with memorizing words and letters, you get to a certain point where you grasp the language of it more intuitively, and even to the point that you can _bend_ the rules. So memorization is always involved on some level, but as a stepping stone to really grasping the style, provided you have the capacity to move beyond simple imitation of the phrases/forms.
One other thing here is that rather than attributing the loss of oral poetry strictly to the emergence of writing, I think it partly dies due to the success of some great poets; jounglers beat out improvisators when copying the "best" is better than improvising, so the process of "meritocracy" ends in a "bloom", after which the plant dies.
I suspect that oral traditions would sometimes die pre-writing because an oral poet's particular formulations became so beloved that people simply imitated them, copying them as nearly as possible (probably favoring shorter works;) and spent time memorizing things exactly rather than understanding the meta-language of the improvisation. This is precisely what I think has happened to European Classical Music; most of the composers were part of a formalized compositional tradition (one version of this is called 'the Aetlier method' iirc) that had them memorizing formulas for cadences and common melodic ideas until they could make compositions themselves, and the best of them could improvise whole pieces. This tradition was always attached to the through-compositional tradition, not because the music was written or there was no improv (or that free improv wasn't something all of these masters could do) but because ensemble requires coordination and you can't coordinate if people are doing things that conflict beyond a certain level. So if you are doing vocal imitation, it's possible to improvise a theme-variation on a motet, but not with four singers, who may know the same language of phrases, but may make choices on the fly that break the harmonic sounds. So in this tradition you have a combination of improvisational sections or pieces and through-composed ensemble work, which for most of the history sat side by side unmolested! I think this is because the way in which music was taught involved teaching one to compose using formulas which create that meta-language, which equipped all trained musicians to both improvise and through-compose.
Something of this sort is possible with poetry.