Sino-Xenic (or Sinoxenic) pronunciations are regular systems for reading Chinese in Japan, Korea and Vietnam, originating in medieval times and the source of large-scale borrowings of Chinese words into the Japanese, Korean and Vietnamese languages, none of which is genetically related to Chinese. The resulting Sino-Japanese, Sino-Korean and Sino-Vietnamese vocabularies now make up a large part of the lexicons of these languages. The pronunciation systems are used alongside modern varieties of Chinese in historical Chinese phonology, particularly the reconstruction of the sounds of Middle Chinese. Some other languages, such as Hmong–Mien and Tai-Kadai languages, also contain large numbers of Chinese loanwords but without the systematic correspondences that characterize Sino-Xenic vocabularies.