bottle up vs sound off

bottle up

verb
  • To prevent (enemy vessels) from leaving an anchorage. 

  • To put into bottles. 

  • To keep suppressed and hidden. 

sound off

verb
  • To hold forth about something in an opinionated manner. 

  • Command instructing a person to confirm that they are present or that some other objective has been met. 

  • Command instructing a person to speak up or acknowledge something. 

How often have the words bottle up and sound off occurred in a corpus of books? (source: Google Ngram Viewer )