Types of Passages Which Easily Reward Comparative Performances
1) Explicit internal reference to the speaker’s non-standard oral performance (CT Miller’s self-professed drunkenness; Criseyde’s “Who yaf me drynke?”; anything said by Chauntecleer and Pertelote [who are talking chickens, in some sense]); the species-individuated voices of the parliamentary “foules” in PoF; characters whose emotional state is explicitly or implicitly described in ways which would shape speech (the Summoner's Tale's sick householder who is "angry as a pissemyre" and "groneth lyk oure boor").
2) Explicit external reference to the speaker’s oral performance (the General Prologue mentions the Friar’s lisp and the Prioress’s nasal French; the Prioress' Tale's "little clergeoun" and other characters who sing or recite sacred text [“O Alma Redemptoris Mater" in PrioressT]).
3) Internal possibilities of characters’ sincerity, irony, anger, lust, comic intent, etc. (MT’s Alison’s response to Hende Nicholas in the kitchen, Chaucer-the-Pilgrim’s reaction to the Cook’s delight at the double-rape concluding the Reeve’s Tale, “Retractions” voice as all Chaucer’s or the Parson’s changing to Chaucer’s at “Wherefore,” & almost anything said by Troilus, Criseyde, Pandarus, Diomede, Calkas, or Elene)