Historical clue formulations

• Early challenge overcome by Joe Biden — 2020-11-30
• Say "Th-th-th-that's all, folks," e.g. — 2010-05-02
• Possible result of anxiety — 2009-06-11
• Sound before "That's all, folks!" — 2009-05-28
• Sing "K-K-K-Katy," say — 2005-10-12
• Job for a speech coach — 2003-08-13
• Talk like th-th-this — 2002-05-13
• Repeat oneself? — 2001-03-18
• Porky Pig's speech — 1995-10-17
• Lack smoothness of speech — 1995-10-05
• Say it again? — 1994-04-03