Xfce4 localization in Guix System for only one exact user

[znavko]

Hello! This is from those question people want just find one or two lines to 
paste in terminal and to get effect.
I did not find solution.
Please, how to make Xfce4 menus (right mouse click, maybe Main Menu) become 
Russian for only one user 'mom'?

As I know, packages are installing using locale settings. So, I need to 
configure my locale and reinstall Xfce4 (reconfigure system).

I have installed locale package as as Guix Manual says [1] with this command:

$ guix install glibc-locales
I have now 'locale' command in guix (but do not know exactly if it is provided 
with glibc-locales? and is it providing with glibc-utf8-locales ?):

$ locale
LANG=en_US.utf8
LC_CTYPE="en_US.utf8"
LC_NUMERIC="en_US.utf8"
LC_TIME="en_US.utf8"
LC_COLLATE="en_US.utf8"
LC_MONETARY="en_US.utf8"
LC_MESSAGES="en_US.utf8"
LC_PAPER="en_US.utf8"
LC_NAME="en_US.utf8"
LC_ADDRESS="en_US.utf8"
LC_TELEPHONE="en_US.utf8"
LC_MEASUREMENT="en_US.utf8"
LC_IDENTIFICATION="en_US.utf8"
LC_ALL=
And I've found in the web the way to change locale that might work on Guix 
System:

$ localedef -c -i ru_RU -f UTF-8 ru_RU.utf8
cannot create temporary file: 
/run/current-system/locale/2.28/locale-archive.g44JbZ: Read-only file system

But as I can see need to do this by sudo user. So it will change locale for 
entire system. But I want localize Xfce4 for only user 'mom'.
Can I do it?
[1] http://guix.gnu.org/manual/en/guix.html#Locales-1