Sir Walter Scott recalls in his book Minstrelsy of the Scottish Border that ‘The Twa Corbies’ was ‘communicated to [him] by Charles Kirkpatrick Sharpe, esq. jun. of Hoddom, as written down, from tradition, by a lady.’  The use of the word ‘Tradition’ suggests that ‘The Twa Corbies’ ballad survived orally. According to Buchan
The nonliterate person does not possess […] visual imagination, words for him cannot be translated into pictorial symbols, they exist in sound groups; his facility for imaginative retention is largely auditory. 
The traditional methods of ballad structure such as form, convention, uncomplicated language, and rhyme create the sound groups that Buchan is suggesting. Whilst assisting the performer and the audience in memorising the ballad, the construction of the ballad ensures that its bones remain intact regardless of time and place. This allows the longevity of the story.
The anonymous ballad, ‘The Twa Corbies’ has a chivalric theme. Morgan suggests that in the chivalric ballad ‘Neither historical figures nor legendary idols escape criticism, [in] the ballads of chivalry [they] serve to strip the façade of honor from their social betters.’  Within a particular genre, the use of common tropes assists in memorising the narrative through fixed characters and themes. This also allows a performer to make a ballad contemporary whilst retaining the familiar narrative. Like most medieval ballads, ‘The Twa Corbies’ begins in Media Res, keeping the narrative brief whilst allowing the audience to quickly interpret the ballad’s intended meaning. The commonality of ballad themes means that multiplicity may occur, for example, ‘The Twa Corbies’ has great similarities to the English ballad ‘The Three Ravens’. Although the narrative of these ballads is similar, the tone sets them apart. ‘The Three Ravens’ conveys an optimistic tone which Morgan suggests ‘upholds the chivalric tradition of romance, complete with references to knightly behaviour, courtly love, and Christian piety’, (Morgan, p.119-120). The sombre tone of ‘The Twa Corbies’ however, implies a negative interpretation of chivalry with a realistic view of a social situation in which the importance of survival is crucial. This is found in the following three lines:
‘His hound is to the hunting gane,
His hawk to fetch the wild-fowl hame,
His lady’s ta’en another mate, 
The abandonment and disregard for the dead knight’s body offers the audience a natural and realistic account of life and death and the nature of survival. These three characters resume living in the most natural way. The theme of survival is clarified in the final line of the stanza:
So we may mak our dinner sweet. (TTC, 12)
This line highlights not only that compassion is essential for survival but also that all creatures are equal, a direct criticism of chivalric hierarchy. The tone of ‘Sir Patrick Spens’, is similar to ‘The Twa Corbies,’ in that it demonstrates the danger of the hierarchal structure, for example
‘O wha is this has duin this deed
An tauld the king o me 
The phrase ‘duin this deed’, suggests that the speaker has already accepted his deadly fate which, predetermines the remainder of the ballad. In addition, these lines not only demonstrate danger of royal hierarchy but also of the Kings right to assume the role of God. The ballad audience however, are already aware that the elderly knight is responsible:
O up and sat an eldern knight (SPS, 5)
The use of ‘O’ at the beginning of the line mimics the form of the traditional hymn. As a result, this technique elevates the position of the knight to God. This allows the audience to question not only the idealism of royalty, but also the hierarchal structure of the royal court and it’s danger of improper decision-making. The effect of tone in both ‘Sir Patrick Spens’ and ‘The Twa Corbies’, in addition to theme, structure and word choice directs the reader to the underlying meaning and intention of the ballad.
The generic ballad form allows the performer to navigate his way through the ballad by creating self-contained narrative frames, or stanzas. Each frame consists of a variety of stylistic conventions that create auditory symbols, instructions, and prompts, essential for the performer and the audience in memorising the song. For example, the opening couplet in ‘The Twa Corbies’ acts as an essential idea, setting the scene of the narrative. The first person speaker recalls an incident in past tense:
As I was walking all alane,
I heard twa corbies making a mane; (TTC, 1.2)
The use the of verbs ‘Walking’ and ‘makin’ rather than ‘walked’ and ‘make’ are coded words which have a dual purpose, firstly to fulfil the rhythm of iambic tetrameter and also to describe movement, firstly from the speaker then followed by the corbies. The progressive verb choices, in addition to the past tense narration demonstrate the continuity of life and the underlying theme of the narrative, which is survival. Performed in thin Scots, the mixed dialect gives the audience a sense of place, whilst acting as a comparison to the English dialect – the dialect of the hierarchal chivalry. In addition, the refrain of the rhyming couplets assist the performer in memorising the sound units whilst allowing the narrative to be adapted and developed within a set structure. In the first couplet ‘all alane’ (TTC, 1) is a triad of assonance, with the ‘a’ sound at the start of the three syllables. This acts as a sound group, important for memorising. In line two, ‘making a mane’ (TTC, 2) is a refrain of consonance. The ‘m’ sound lands at the beginning of a two-syllable word followed by a one-syllable word. This elongates the sentence making the ‘mane’ onomatopoeia. It is therefore the manipulation of sounds and beats that aid the speakers memory rather than the words themselves.
The symbolism of the corbies – a Scottish word for ravens, has various mythological connotations, one of which is that ‘Ravens as birds of knowledge appear throughout myth, especially in Odin’s two ravens, Huginn (Thought) and Muninn (Memory)’.  This tale will have been familiar to audiences in medieval times, therefore informing the audience of the role of the corbies within in this ballad to represent thought and memory, crucial for the survival of the narrative.
There is a tense change in the final line of the first stanza when the narrative changes into dialogue:
‘Where sall we gang and dine to-day?’(TTC, 4)
This change indicates a scene break that allows the oral storyteller to move on to a different frame with different conventions. The leaping between scenes or frames requires the audience to read between the lines and flesh out the narrative themselves. This closing line in stanza one is the last line in a long sentence, moving from past to present. This demonstrates movement in time, also survival and tradition – which is the link between past and present. The introduction of ‘we’ prompts audience participation, a further mode of memorising.
In stanza two, the speaker uses ironic juxtaposition in a couplet. The ‘auld fail dyke’ (TTC, 4) conceals ‘a new slain knight’ (TTC, 5). ‘Auld’ is the primary word, situated before ‘new’ in the stanza. This gives the former superiority. Not only does this romanticise an older way of life but also demonstrates the strength of the old through the symbolism of the wall and its survival. These conventions are important to allow the framing and unfolding of each stanza, important for prompting memory, and continuity.
The generic form found in ‘Sir Patrick Spens’ is the most commonly found traditional ballad form; a four foot line followed by a three foot line. The consistent rhyming scheme, ABCB allows the framing of each stanza, which, like ‘The Twa Corbies’ is an arrangement of quatrains. Whilst this ballad is greater in length, the techniques are consistent of the ballad tradition. The sound refrains such as ‘whare will’ (SPS, 3) creates a sound like the wind, whilst ‘skeely skipper’ (SPS, 3) makes a storm like sound. These techniques not only create an ambiance, but also are sound symbols. Due to the length of this ballad, the refrain is demonstrated on a wider scale, such as ‘To Norway’ is repeated three times in stanza four. Using a variety of different conventions within each frame, aids the memory of the oral storyteller through the use of sound, symbols and prompts.
Whilst ‘Sir Patrick Spens’ is a much larger poem in length than ‘The Twa Corbies’ the techniques of style and convention are similar. The overall effect of the style and convention in both ballads is to aid the memory of the performer whilst guiding and prompting himself and the audience. The purpose of this is to deliver a story within the bones of a well-known narrative theme, which, through auditory symbols and sound groups, makes it adaptable as it is re-told and reworked over time. Moreover, whilst many medieval ballads adopt a familiar theme, resulting in multiplicity, the tone and dialect set them apart.
Anonymous, ‘Sir Patrick Spens’, in The Penguin Book of Scottish Verse, ed. by Robert Crawford and Mick Imlah (London: Penguin Books, 2006)
Anonymous, ‘The Twa Corbies’, in The Penguin Book of Scottish Verse, ed. by Robert Crawford and Mick Imlah (London: Penguin Books, 2006)
Buchan, David, The Ballad and the Folk (East Linton: Tuckwell Press, 1997)
Frankel, Valerie Estelle, The Symbolism and Sources of Outlander: The Scottish Fairies, Folklore, Ballads, Magic and Meanings that Inspired the Series (North Carolina: McFarland and Company, 2015)
Morgan, Gwendolyn A., Medieval Ballads: Chivalry, Romance, and Everyday Life. A Critical Anthology (New York: Peter Lang Publishing, 1996)
Scott, Sir Walter, Minstrelsy of the Scottish Border, 2nd edn (Edinburgh: James Ballantyne, 1803)