trill
noun /trɪl/
  /trɪl/
- a repeated short, high sound made, for example, by somebody’s voice or by a bird(人的)颤声,短促尖声;(鸟的)啼啭,唧唧啾啾 
- (music音乐 颤音 
- (also roll)(phonetics语音学 颤音 
词源mid 17th cent.: from Italian trillo (noun), trillare (verb).