I dont know how to change locale to rusian but yuo can force mc to use english by deleteing polish files in sys/locale/PL  delete folder PL and in /sys/mc/ delete mc.hint.pl and mc.help.pl reatart mc and it'l be in english
if youu find out how to change local pleas share.
Greeting Kradovan
forget this found out how to change locale

go to folder sys/etc/

use editor to edit file "profile"

inside file you'll find

export LC_CTYPE=pl_PL
export LC_LANG=pl_PL
export LC_TIME=pl_PL
export LC_ALL=pl_PL
export LC_MESSAGES=pl_PL
export LC=pl_PL
export LC_LOCALE=pl_PL
export LC_COLLATE=pl_PL
export LC_MONETARY=pl_PL
export LC_NUMERICS=pl_PL
export LANG=pl_PL

change pl_PL to ru_RU or uk_UK save file start mc and it will be in rusian or english dependig on your change.
Greeting Kradovan