It's all rubbish when I use a non-ASCII language
From NSIS Wiki
|Author: virtlink (talk, contrib)|
- When using a non-ASCII language with NSIS, the characters are shown incorrectly.
- NSIS uses MBCS and does not support Unicode languages (FR #1238132).
- Check that you have installed the Windows support for that language, and check that the specified language is the default language for non-Unicode programs. You can check or set it in the Regional and Language Options control panel. Click the Advanced tab and look in the Language for non-Unicode programs groupbox.
A Unicode-compatible version of NSIS is currently under development and its code changes under evaluation for inclusion for a future release. Fore more information, see: Unicode NSIS