Simple, Formulaic
The poem's long, the fighting's bloody, but, gee, does this poet keep things simple—at least on a sentence level.
The language is plain without a lot of description. Sure, you can trip up on all that armor bling, like the hauberks and byrnies and carbuncles, but adjectives and adverbs are scarce. Plus, the sentences themselves tend to be straightforward clauses with subjects verbing things to objects.
And instead of chaining these sentences together with conjunctions like "therefore" and "because of this," the poet skips the connecting words altogether and lays the sentences out, one after the other, like beads on a necklace. Called parataxis, this style leaves the reader to make the causal connections between sentences.
When you keep your sentences simple, you limit variation. That's right, folks, the Song of Roland is mind-numbingly repetitive. Remember all those pagan-on-Frank clashes, when each pagan was cleft in two and tossed a "spear's-throw" from his horse? Or all the stanzas that describe some sad Frankish death and end with a punchy summarizing line like, "The French say: "God! What a pity to lose such a worthy man!" (114.1501)?
In addition to keeping it simple, this poet keeps it formulaic. Boring, right? Not so fast. Not only does this structure the poem and give its 291 stanzas some coherence; it was also essential to the poem's survival. Because Roland was composed and passed down orally, formulaic phrases and stanzas were critical to people remembering them.
Plus, even though the poet isn't shy about what is Good and what is Evil, he keeps the stanzas focused on actions rather than abstractions. This is a chanson de geste we're talking about (head up to "In a Nutshell" to find out more). That means that big ideas and philosophies take a backseat while warfare of all varieties hogs the spotlight.
Speaking of stanzas, in chansons de geste, the stanza unit is called a laisse. Each laisse contains a varying number of ten-syllable lines, which are split by a caesura, or pause, that usually comes after the fourth syllable. You'll also notice that these lines don't rhyme—not even in the original French. Instead, they are connected by assonance: in a given laisse, every line ends in a syllable of the same vowel sound. English translations usually don't even try to replicate this, but if they did it would look more like this:
The sword sliced the hog
Whose brain spilled on the sod
rather than this:
The sword sliced the hog,
Whose brain spilled on the bog.
"Hog" and "sod" are connected by assonance; "hog" and "bog" are connected by rhyme.
Despite its formulaic action-based simplicity, the poem does do wild stylistic things when it comes to laisses similaires, or parallel laisses. These are consecutive laisses that describe the same event but with slightly different details or from a slightly different viewpoint.
They usually occur at the most dramatic moments in the poem, when tensions are high and people's reactions are key, like when Ganelon accepts his nomination as the envoy and when Roland accepts his nomination as leader of the rearguard, when Roland and Oliver argue about the oliphant, and when Roland dies.
This technique can be disorienting because at first it gives the impression that something happened three times and differently each time. Instead, think of it as the poet slowing the action down for a bit, considering something from a few different angles, intensifying the emotion, all in order to build dramatic effect.
When Roland dies, for instance, it stretches across so many similar stanzas that you might think he's drifting into delirium and repeating himself without knowing it. In fact, the poet might be trying to reproduce exactly that. But even more important is the slowing-down effect. This is the most tragic moment in a very tragic poem, and the poet wants to make sure that we truly savor it, meditating on Roland's last moments and thoughts as time is suspended—a little like Charlemagne halting the sun for three days.
Finally, you may notice that the tense swings back and forth between past and present, giving a sense of immediacy and then of distance. Example:
Because of the vexation he feels, he bewails his miserable lot.
Now a knight came before him. (277.3817-18)
No one's really sure why the poet chose to do this. Sometimes the change sharpens the sense of drama, other times it seems totally random.