In the original font file that letter exists, but nevertheless I tested your suggestion.
...and - Still doesn't working.
Tested on: LinLibertine_RB.otf, DejaVuSansMono.ttf (from game),
and: Cantarell-Bold.otf, arial.ttf (from linux)
Then tested the same fonts by starting the game with the parameter "--use-font=...", then with parameter "--enable-legacyfonts", then (the last test was) with changed "ISO639-1=pl" to "ISO639-2=pol".
The result is still negative.
It looks to me as the game couldn't connect
existing letter from font file with a
properly working keyboard shortcut.
For end, I attaching the entire configuration (original) of fonts because these variables are so many that this problem can hide somewhere here too. For example, somewhere in that mysterious "*-*-*-*-"
.
; Font configuration for FTGL
; Before using an alternative font, please verify license compatibility
ISO639-1=pl
NativeLanguageName=język polski, polszczyzna
MEGAGLEST_FONT=$APPLICATIONDATAPATH/data/core/fonts/LinBiolinum_RB.ttf
MEGAGLEST_FONT_FAMILY=Linux Biolinum O:style=Bold
FONT_SCALE_SIZE=$USE_DEFAULT_LANGUAGE_VALUE
FONT_SCALE_CENTERH_FACTOR=$USE_DEFAULT_LANGUAGE_VALUE
FONT_BASE_SIZE=$USE_DEFAULT_LANGUAGE_VALUE
FONT_CHARCOUNT=$USE_DEFAULT_LANGUAGE_VALUE
FONT_CHARSET=$USE_DEFAULT_LANGUAGE_VALUE
FONT_HEIGHT_TEXT=yW
FONT_MULTIBYTE=0
FONT_RIGHTTOLEFT=0
FONT_TYPENAME=Times New Roman
FontDisplayBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontDisplayPostfix=-*-*-*-*-*-*-*
FontDisplayPrefix=-*-arial-*-r-*-*-
FontDisplaySmallBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontMenuNormalBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontMenuNormalPostfix=-*-*-*-*-*-*-*
FontMenuNormalPrefix=-*-arial-*-r-*-*-
FontMenuBigBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontMenuBigPostfix=-*-*-*-*-*-*-*
FontMenuBigPrefix=-*-arial-*-r-*-*-
FontMenuVeryBigBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontConsoleBaseSize=$USE_DEFAULT_LANGUAGE_VALUE
FontConsolePostfix=-*-*-*-*-*-*-*
FontConsolePrefix=-*-arial-*-r-*-*-