He seyde he lovede and was biloved no thyng.
Of swich matere made he manye layes,
Songes, compleintes, roundels, virelayes.
(Franklin's Tale V.946-48).
The English lyric, before Chaucer, was characterized by a simple directness and purity of diction, largely untouched by French influences. This is true even of the celebrated Harley Lyrics, which show a heavy influence of French ideas about love.
Chaucer knew this tradition and it seems likely that many of the songs and "lecherous lays" he acknowledges having written (in his Retractions, CT X.1087) were in this simple style. What they might have been like is shown by the lyrics quoted in Chaucer's poetry -- the fragment in the Knight's Tale (CT I.1510-12), the lyrics embedded in the Book of the Duchess (BD 475-486, 1175-1180), and the roundel that concludes the Parliament of Fowls.
For a very readable selection of such Middle English lyrics, see the Anthology of Middle English Literature, created by Anniina Jokinen.
For a fifteenth-century example of the plain style by a writer who knew Chaucer's works see the English poems of Charles d'Orleans; Click here for two brief examples.
Chaucer introduced the elaborate high style into the English lyric tradition, and adapted the French balade into English; his surviving lyrics are almost all in that mode. So too were those lyrics of many of his successors. For an elaborate sample of the high style see Lydgate's Epithalamion for the Duke of Gloucester. An even more egregious example is Benedict Burgh's Letter to Lydgate. Chaucer's best works in this style are the "Boethian lyrics," most notably the great balade on Truth.
For a bibliography of scholarly and critical works on Middle English Lyrics see click here.