One evening, I listened to a discussion over amateur radio in which
a person who spoke Japanese was telling a group of fellow amateur radio
operators how to say digits in Japanese.  If I recall, the number 4
had two different sounds, one being  shi  and the other being  yong.  If
there were two 4's, one was always to say "yong yong," and never the double
version of the other sound.

Martin McCormick