Possible Clues:

• "Is that so?," or a hint to the communication methods found in this puzzle's circled letters
• Accusation delivered to silent person that is so obvious!
• Liberal excluded from US only today, outrageous, really!
• Really, could they be one's unconscious thoughts? (3,3'1,3)
• 'Really?!'
• 'How astonishing,' one thinks
• The solver is speechless? Well I never
• ''Is that so?''
• "Gosh!," to a mime?
• Conversation filler