The document discusses three main categories of barriers to business communication: external barriers, organizational barriers, and personal barriers. External barriers include semantic barriers due to differences in interpretation and emotional/psychological barriers like inattention, perceptual biases, information loss over transmission, premature evaluation, overreliance on written communication, and distrust of the communicator. Organizational barriers consist of unsupportive communication policies, status relationships between superiors and subordinates, complex organizational structures, restrictive rules and regulations, and information overload. Personal barriers involve superiors' negative attitudes, fear of losing authority, lack of confidence or time, and ignorance of communication's importance.