raucous vs sibilant

raucous

adj
  • Harsh and rough-sounding. 

  • Loud and annoying. 

  • Disorderly and boisterous. 

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. 

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