dudou vs yem

dudou

noun
  • A traditional Chinese female undergarment, usually made of silk, covering the breasts and belly, and tied at the neck and waist; a Chinese underbodice. 

  • Its equivalents in Vietnam and other East Asian countries. 

yem

noun
  • A Vietnamese form of underbodice; a dudou, its Chinese progenitor and equivalent. 

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