ballad vs chanson

ballad

noun
  • A slow romantic song. 

  • A kind of narrative poem, adapted for recitation or singing; especially, a sentimental or romantic poem in short stanzas. 

verb
  • To compose or sing ballads. 

chanson

noun
  • Any song with French words, but more specifically a classic, lyric-driven French song. 

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