Troilus and Criseyde is written in rhyme royal stanzas of seven lines rhyming ababbcc. Despite the various subdivisions within the narrative (for example its proems, songs, letters, prayers, and apostrophes), Chaucer doesn’t vary the form of his stanzas as a French dit amoureux might for inset lyrics but keeps to this stanza throughout. In later Middle English, the term balade referred not only to a fixed-form lyric but also to the stanza forms generally used within such lyrics. To write in balade was to write stanzaically, most often in seven-line rhyme royal stanzas, though the term ‘rhyme royal’ was coined later during the sixteenth century.
One of poetry’s special qualities is that it can be language made metrical, structured with repeating units and patterns of rhythm. Like music, it has a regular beat, though as with music you can temporarily step away from this repeating pattern, knowing that the beat can be re-found. Poems written in Middle English are written in lots of different types of metrical systems (for example octosyllabics, alliterative long lines or decasyllabics, amongst several other types and mixtures), some unique to each author or work. So your first job, if you’re analysing a Middle English poem, is to turn to the introduction of your edition and find out about the specific metrical practice of the particular poem you are reading. For a great introduction to the metre of Middle English alliterative verse, see this website. Much of what I say in the post below only really works for Chaucer’s Troilus.
Poetry has licence to manipulate ‘reality’ (for example in metaphor or allegory) and also to distort language into artificial and deliberate patterns which you would be much less likely to find in everyday speech. This is the origin of the idea of ‘poetic licence’. One of poetry’s licences is its licence to vary the expected or conventional order of words in a sentence, without these unusual orders being considered ‘wrong’ or ‘ungrammatical’.
Middle English poetry relies on repetition to create its rhythms and artfulness. Metre and rhyme-schemes are in themselves patterns of repetition, patterns of alternate stress and of repeated rhyme-sounds. Repetitions can be consciously planned by poets, built into their poetry even as they juggle the demands of meaning, metre and rhyme. Or they can be found in poems by readers who can find meaning and coherence in something a poet has not consciously planned. As well as the repetition of words and phrases, grammatical structures can be repeated (i.e. the same syntactical pattern repeated with different words in each instance).
The word enjambment comes from the French verb enjamber, meaning to span, straddle or stride, literally to step seamlessly from one line of verse to the next. Looking at punctuation often seems a good way to spot it. If there’s punctuation at the end of the line, the line is end-stopped, i.e. you pause at the end of the line. If there’s no punctuation, then the line is enjambed (or run-on, an alternative term) because you carry on reading seamlessly over the line-break.
Alliteration is the repetition of the same or similar sounds at the beginning of a word. In modern definitions, alliteration usually refers to the repetition of consonants or consonant clusters (i.e. str, th). Some Middle English poetry uses alliteration in every single line as part of its metre and form. This is structural alliteration, alliteration which is part of the structure of every line. This post is NOT discussing how to talk about structural alliteration in alliterative verse, but rather how to talk about sporadic, ornamental alliteration in Middle English non-alliterative verse.
The repetition of sound (whether rhyme or alliteration) is part of what gives the language of Middle English poetry its musicality, the patterned artifice which signals that it is different from everyday speech. In rhyming verse, the rhyme at the end of each line (as well as the metrical pattern of the line) divides its language up into equal units. As well as marking the individual line, rhymes indicate greater divisions, whether these be pairs of lines linked together to form couplets (aabbcc), or larger patterns of quatrains (abab), tail-rhyme stanzas (aabaab), seven-line rhyme royal stanzas (ababbcc) or eight-line ballade stanzas (ababbcbc).