mobile phone vs walkie-talkie

mobile phone

noun
  • A portable telephone that connects with the telephone network over radio wave transmission. 

walkie-talkie

noun
  • A portable, bi-directional radio transceiver, usually as a pair. 

  • A walk and talk. 

How often have the words mobile phone and walkie-talkie occurred in a corpus of books? (source: Google Ngram Viewer )