We borrow the Greek term, "lyric," to describe a genre of poems that usually are short, and usually are meant to be sung or recited aloud, sometimes to the accompaniment of musical instruments (viz., the lyre or harp, but also various medieval stringed instruments intended to be plucked or bowed). For this reason, lyric poems in early languages nearly always rhyme, to take advantage of the musical element of phonology, and they often use alliteration, assonance, and consonance to amplify rhythmic patterns. After the end of Classical Latin in about the sixth century, poets writing in the vernacular "Romance" European languages that were based on Latin tended to lose their interest in or ability to count strict meter. Rather than writing in "feet" (e.g., iambic pentameter), they composed in verse lines with varying numbers of syllables that were organized around predictable patterns of "stress" or emphasis, such as the four-stress lines in which most of Chaucer's lyrics were written.
Interpretation of lyrics usually pays great attention to the interplay of sound and sense, noting patterns which use sound to reinforce or undercut the sense of what the poem is saying. New Critical close-reading analysis always forms the first stage in any competent reading, but from the basis of a sound close reading, scholars often incorporate any of a variety of other theoretical approaches, including Feminist, Marxist, Psychoanalytic, New Historicist, Structuralist, or Deconstructive interpretations. Some lyrics even can play "Reader-Response" games with their readers. I would argue, for instance, that Chaucer's "To Rosamounde" is very unlikely to be seriously addressing an eligible female the speaker is attempting to seduce, but rather it shows signs of being addressed to a very young girl in a gentle parody of the lover's traditional "complaint." (In fact, I think most of Chaucer's "love lyrics" appear to be radical departures from older, more traditional poems.) For this reason, it is important to remember that the persona who performs a lyric usually is an unstable device, somewhere between the author's own voice and any other possible fictional construct one can imagine, from gods to animals to abstractions like "Time" or "Death." Similarly, the personae mentioned by the poem's primary speaker also may be deceptive, or even imaginary, though they also may be real persons (e.g., "Bukton" and "Vache" and "Edward II," the subjects of "envoys" which conclude several of Chaucer's lyrics. T.S. Eliot's The Three Voices of Poetry (1954) argued that lyric poetry was meant to be overheard by its readers because the typical situation assumed by the poem was a speaker addressing someone or something other than the readers. Nevertheless, Eliot also believed that lyrics were not expressions of personality, but rather an "escape from personality," a thesis which may work better for some poems, and some poets, than others, but which the interpreter always should keep in mind as a possibility before attributing any lyric directly to its author's personal opinions. Remember the existence of irony, parody, comedy, and satire, all of which often involve poetic speakers saying things that the author hopes readers are bright enough to "read against" in order to detect alternate and more important truths.