doudu vs dudou

doudu

noun
  • Synonym of dudou. 

dudou

noun
  • Its equivalents in Vietnam and other East Asian countries. 

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

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