WordNet (r) 3.0 (2006):

unliterary
    adj 1: marked by lack of affectation or pedantry; "her talk was
           very unliterary"- W.D.Howells [syn: unliterary,
           nonliterary]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "unliterary":
   Gothic, Philistine, barbarous, bookless, colloquial, common,
   conversational, deceived, everyday, familiar,
   functionally illiterate, grammarless, heathen, hoodwinked,
   ill-educated, illiterate, informal, led astray, lowbrow,
   misinformed, misinstructed, mistaught, nonintellectual,
   nonstandard, pagan, rude, spoken, substandard, unbooked, unbookish,
   unbooklearned, unbriefed, uncultivated, uncultured, unedified,
   uneducated, unerudite, unguided, uninstructed, unintellectual,
   unlearned, unlettered, unread, unrefined, unscholarly, unschooled,
   unstudied, unstudious, untaught, untutored, vernacular