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. You can set the option to use the wider character set in the extension

Further Information

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