Between 60 and 68 AD, Pliny gathered linguistic observations on passages from authors he had read in preparation for composing the Naturalis historia. He then chose to organize and publish them in eight books titled Dubius sermo. The study of approximately 130 surviving fragments reveals several insights: (1) Pliny assigns authority not only to major poets and prose writers but also to minor ones, letter writers, and even technical writers; (2) as the documentation expands, scholas- tic norms diminish in importance, and Latin takes on the character of a dubius sermo, where speakers lack secure references; (3) the expressive modes found in literature somewhat evade assessment for correctness, because if authors deviate from norms, they do so knowingly.