To begin to analyze The Song of Roland, we must start with its smallest units. Like other chansons de geste—this term is French for "song of deeds" and refers to the epic poems of the Middle Ages recounting the exploits of heroes like Charlemagne, Guillaume, and Girart—The Song of Roland is divided into verse paragraphs of varying length called laisses. Many of the poetic features of The Song of Roland are lost when it is translated from the dialect of Old French in which it was composed. The first laisse, in the original, may serve to demonstrate these features:
Carles li reis, nostre emperere magnes, Set anz tuz plains ad estet en Espaigne: Tresqu'en la mer cunquist la tere altaigne. N'i ad castel ki devant lui remaigne; Mur ne citet n'i est remes a fraindre, Fors Sarraguce, ki est en une muntaigne. Li reis Marsilie la tient, ki Deu nen aimet. Mahumet sert e Apollin recleimet: Nes poet guarder que mals ne l'i ateignet. AOI.
Each laisse is held together by several poetic devices. Each line consists of ten syllables, divided roughly down the middle by a pause or rest. The rhythm of the line is formed by strong stresses falling on the fourth and tenth syllables. Within a single laisse, the separate lines are linked by assonance—a partial rhyme in which the accented vowel sounds are the same but the consonants differ, as in "brave" and "vain," for instance. The vowel sound repeated through one laisse never carries on to the next. Since the poet has divided his song into laisses according to the sense and not any standard length—for instance, a new laisse will begin when one combat or speech ends and the next begins—this use of assonance reinforces the divisions of plot, of action.
The repeated "AOI," found throughout the poem, usually but not always at the end of a laisse, is something of a mystery. Nothing of the sort is found in any other chanson de geste or Old French manuscript of any sort. There are many conjectures about it—perhaps it is an obscure abbreviation of alleluia or Amen or ainsi soit it ("so be it"), perhaps it is some sort of musical notation—but in any case it certainly marks out changes of scene or atmosphere and moments of special significance in the action. It calls on us to pay particular attention when it crops up.
The Song of Roland is structured so as to be symmetrical through and through. The poem is centered around four great scenes which balance each other perfectly. At the very beginning we have Ganelon's crime; at the very end we have his punishment. Around the center, Roland's martyrdom and Charlemagne's vengeance face and mirror each other, both taking the shape of great battles, presented in a parallel order, at Roncesvals. Ganelon's successful treachery and Roland's early death temporarily set the scales of good and evil askew; the events of the rest of the poem then set them right.
The many repetitions and parallel passages of the poem contribute to the total sense of purpose and symmetry. For instance, the similarities between how the battle between Roland's rear guard and Marsilla's army and the battle between Charlemagne's and Baligant's men reinforce the poet's point that one battle is the mirror-image of the other, that Charlemagne's triumph over Baligant is perfect revenge for the Saracen ambush. The order in which the two battles are presented is the same, as it must be for them to balance each other properly; first there is the inventory of the two opposing forces as they assemble themselves, then, when they meet on the field, the threats and boasts and first blows. Each one-on-one combat, besides the most remarkable and important ones, such as that between Charlemagne and Baligant, takes up one laisse, and all are described in the same language. Comparing the various rather gory ways in which the warriors kill each other, one sees immediately that each description is a slight variation on all the others. Ideally, the effect of such repetition is a sense of ceremonious consistency and rhythm.
Rather than running along at a consistent pace, the narrative consists of certain scenes where time is slowed down so much that it almost stands still, suspending the noble and the wicked gestures of the characters mid-air, with bits of quick summary providing the connection from one tableau to the next. This rhythm is particularly clear and easy to pick out toward the beginning of the poem, in the first fifty or so laisses. After some quick exposition in the first laisse, we get the council of Marsilla presented as if it were a drama. The poet summarizes nothing; he describes the stage of the action, the "terrace of blue marble" (2.12) and then gives us the speeches of Marsilla's advisors in full. The story is conveyed in this section by dialogue, not by running commentary. Then, after another quick laisse of summary, telling how Marsilla's messengers rode out to Charles's camp, we go back to the same slow, dramatic mode of presentation that was used for Marsilla's council for the conversation between Marsilla's envoys and Charlemagne. This alternating, fast-slow-fast-slow rhythm, interspersing quick pieces of narrative between long dramatic scenes at regular intervals, is characteristic.