Set Windows application to use a different language than the OS default
By default Crossover will get your language and format style from the host operating system. You can manually specify a locale by editing the cxbottle.conf file located in each bottle Crossover creates.
To locate the cxbottle.conf file click the Bottles button in the top-left of the Crossover window, select the appropriate bottle, click the gear menu in the bottom-left and pick Open C: Drive. Go up one level to find the cxbottle.conf file on same directory level as the drive_c folder.
In cxbottle.conf under the EnvironmentVariables section add a new entry for the locale you want to use. For example to set the bottle to Russian you'd enter:
"LC_ALL" = "ru_RU.UTF-8"
Locales that should work are:
These are the UTF-8 locales that are present in OS X's /usr/share/locale/ directory, which the "legacy" directory that wine uses for locale information. Other locales not listed above (for instance, es_MX for Mexico or es_GT for Guatemala) will not work at present.