Why I see man pages in English? In console "man acos" returns text in Russian. Can I fix it?

ACOS(3)            Linux Programmer’s Manual            ACOS(3)

NAME
       acos, acosf, acosl - arc cosine function

SYNOPSIS
       #include <math.h>

       double acos(double x);
       float acosf(float x);
       long double acosl(long double x);

       Link with -lm.

P.S.
tester@Tribeca-desktop:~$ ls /usr/share/man/ru/
man1  man2  man3  man4  man5  man6  man7  man8
tester@Tribeca-desktop:~$ ls /usr/share/man/ru/man3/
abs.3.gz     cos.3.gz      j1.3.gz       sqrt.3.gz         strncpy.3.gz
acos.3.gz    cosh.3.gz     jn.3.gz       strcasecmp.3.gz   strpbrk.3.gz
acosh.3.gz   erf.3.gz      labs.3.gz     strcat.3.gz       strrchr.3.gz
asin.3.gz    erfc.3.gz     ldexp.3.gz    strchr.3.gz       strsep.3.gz
asinh.3.gz   exp.3.gz      lgamma.3.gz   strcmp.3.gz       strspn.3.gz
atan2.3.gz   fabs.3.gz     llab.3.gz     strcoll.3.gz      strstr.3.gz
atan.3.gz    floor.3.gz    log10.3.gz    strcpy.3.gz       strtok.3.gz
atanh.3.gz   fmod.3.gz     log.3.gz      strcspn.3.gz      strtok_r.3.gz
atof.3.gz    free.3.gz     malloc.3.gz   strdup.3.gz       strxfrm.3.gz
atoi.3.gz    frexp.3.gz    modf.3.gz     strfry.3.gz       tan.3.gz
atol.3.gz    hypot.3.gz    pow.3.gz      string.3.gz       tanh.3.gz
atoll.3.gz   imaxabs.3.gz  realloc.3.gz  strlen.3.gz       y0.3.gz
atoq.3.gz    index.3.gz    rindex.3.gz   strncasecmp.3.gz  y1.3.gz
calloc.3.gz  intro.3.gz    sin.3.gz      strncat.3.gz      yn.3.gz
ceil.3.gz    j0.3.gz       sinh.3.gz     strncmp.3.gz