chirruping vs sibilant

chirruping

noun

  • The act of producing a chirrup sound. 

sibilant

noun

  • A consonant having a hissing or hushing sound such as the s or sh in sack or shack. 

adj

  • Characterized by a hissing or hushing sound such as the s or sh in sack or shack. 

How often have the words chirruping and sibilant occurred in a corpus of books? (source: Google Ngram Viewer )