Historical clue formulations

• Musical flutter — 2026-08-25
• Pianist's flourish — 2025-09-12
• Pronounce "rr" in Spanish, say — 2023-10-24
• Warble — 2017-11-19
• Sing like a bird — 2015-02-23
• Shake in an opera house — 2014-03-14
• High-pitched warble — 2013-02-18
• Diva's effect — 2008-01-27
• Fluttering sound — 2007-07-29
• Pronounce an "r" like a Scot — 2001-06-27
• Flutist's embellishment — 2000-03-12
• Bird's sound — 1999-03-10
• Voice lesson topic — 1998-11-15
• Chirrup — 1998-04-05
• Coloratura's specialty — 1997-08-10
• Sutherland specialty — 1996-09-04
• Vibrato sound — 1994-02-20