sibilant vs stridulant

sibilant

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

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

stridulant

adj
  • Making a stridulating sound. 

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