a cappella vs recitative

a cappella

noun
  • A vocal performance with no instrumental accompaniment. 

adv
  • In a manner of a choir with no instrumental accompaniment; literally, "in the style of the (Sistine) Chapel (in Rome)", such as a musical Mass done a cappella. 

adj
  • Singing solely or mainly without instrumental accompaniment. 

  • Related to a form of purely vocal music mostly associated with American college performance groups. 

recitative

noun
  • dialogue, in an opera etc, that, rather than being sung as an aria, is reproduced with the rhythms of normal speech, often with simple musical accompaniment or harpsichord continuo, serving to expound the plot 

adj
  • of a recital 

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