In high school and junior-high on school Japan, the symbol x' is usually pronounced as x dash'. However, in universities it is also read as x prime'. I think in teachers in university is strongly influenced by Americans. I read it in both way in a university.

In high school and junior-high school in Japan, the symbol x' is usually pronounced as "x dash". However, in universities it is also read as "x prime". I think teachers in university are strongly influenced by Americans. I read it in both ways in a university.