Even so, Orduña does not claim this comparison to be a proof of a family relation between Iberian and Basque, but rather owing to Iberian loanwords in the Basque language. In contrast, Ferrer believes that the similarities could be caused due to both the genetic relationship or the loan, but indicates that the loan of the entire system of numerals is rare (but has known to occur such as the case of Middle Chinese numeral being borrowed wholesale into Vietnamese, Japanese, Korean and Thai).