WOW, so active discussion!

OS - Windows & Mac OS X, both

Programs - most system and many others. 

Keyboard layouts - I mean mostly non latin (see
http://en.wikipedia.org/wiki/Keyboard_layout#Keyboard_layouts_for_non-Roman_alphabetic_scripts)

In case of russian keyboard layout i have in place of latin char 'x'
russian letter 'ч', and want to call <<Cut>> command by pressing this
hot key when keyboard really sent to application some like Ctrl+Ч too

In Windows we have messages WM_KeyDown and WM_KeyUp that send always key
index, stored as constants (defined in windows.h or messages.h) like
wk_return, wk_F1, etc. For letter keys, messages come with codes that
always equal to index of similar uppercase latin chars. for example,
first key code in middle row equal ord ('A') = 65. And in context of
russian layout this code translated to Cyrillic letter Ф and sent to
window with next message wm_char. Hot key handling based on WM_KeyDown,
nor WM_Char  

P.S.: Samples of localized showing of the hot keys in menu based on
interface language or current keyboard layout I can't find right now,
but i remember that I have this experience. This is feature not
necessary, because reading some like Ctrl+Ч near menu Cut is really
frustrating.