adjective satellite (s)

• having little acquaintance with writing(adj.all)

  Example:
  Special tutorials to assist the unlettered sector of society.
  

  Synonym:
  analphabetic
  

  source: wordnet30
• uneducated in general; lacking knowledge or sophistication(adj.all)

  Example:
  Exhibiting contempt for his unlettered companions.
  

  Synonym:
  ignorant, nescient, unlearned
  

  source: wordnet30