When you are working in the MakeCode editor in a translated language (ie. not English) you will find that special characters used in strings do not appear on the micro:bit display or MakeCode simulator.

string using non-printable charactersstring using printable characters
Does not workWorks

This is because the MakeCode software and the micro:bit hardware do not currently support displaying the full range of ASCII code characters only the characters that fall within a 'printable range' (32-127). Other characters will display as spaces, so they will not be visible on the screen.

If you would like to be able to use characters outside this range, consider building a MakeCode Extension, similar to this one for Katakana.

Further Information

You can find more discussion on this issue on the micro:bit runtime software repository