The "fifty sounds" are not really fifty in number. There are only about forty-six of them, and in modern times they are arranged as follows, in an order called "gojuuonzu" ("fifty-sound table"):

 a   i   u   e   o
ka  ki  ku  ke  ko
sa shi  su  se  so
ta chi tsu  te  to
na  ni  nu  ne  no
ha  hi  fu  he  ho
ma  mi  mu  me  mo
ya      yu      yo
ra  ri  ru  re  ro
wa              wo

The above table is to be read by rows. It starts a, i, u, e, o, ka, ki,...
This is NOT a complete list of sounds in the Japanese language!