Historical clue formulations

• Informal assent — 2018-03-25
• "Uh-huh" — 2014-09-06
• Casual assent — 2013-08-02
• Mumbled assent — 2006-04-02
• "Uh-huh" — 2005-08-12
• Informal assent — 2004-08-01
• Quick assent — 2004-06-06
• "Uh-huh" — 2003-03-20
• Slangy assent — 1995-06-18