nonsense syllable       
noun [ C ]  language specialized uk/ˈnɒn.səns ˌsɪl.ə.bəl/ us/ˈnɑːn.sens ˌsɪl.ə.bəl/
 无意义音节(不存在于一门语言中的音节)
a syllable (= a single unit of speech that is either a whole word or part of a word) that is invented and has no meaning in a language
  The child repeated the nonsense syllables "boo di doo doo". 小孩咿咿呀呀地重复着“boo di doo doo”这几个无意义的音节。 
 Hypnosis does not increase the recall of meaningless information like nonsense syllables. 催眠不会增加对无意义信息的回忆,比如无意义的音节。 
 - More examples
 - Scatting is a set of nonsense syllables set to music.
 - A woman dressed in white recited nonsense syllables.
 - We know a lot about how people learn nonsense syllables.