babish vs sibilant

babish

adj

  • Like a babe; childish; babyish. 

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 babish and sibilant occurred in a corpus of books? (source: Google Ngram Viewer )