use warnings;
use strict;

my %trans = (
  q{t'i} => 'ти',
  q{t'a} => 'тя',
  q{t'u} => 'тю',
  q{t'e} => 'те',
  );

my @signs = sort {length($b) <=> length($a)} keys %trans;
@signs = map quotemeta($_), @signs;
my $re = join '|', @signs, '.';
print "original: '$re' \n";

my ($cyril) =
    map  qr{ $_ }xms,
    join ' | ',
    map  quotemeta,
    sort { length($b) <=> length($a) }
    keys %trans
    ;
print "suggested: $cyril \n";

my $text = "t'i don't understand t'any cyrillic.";
print "raw: [$text] \n";
$text =~ s{ ($cyril) }{$trans{$1}}xmsgo;
print "translation: [$text] \n";

##</code><code>##

c:\@Work\Perl\monks\nikop>perl xlate_cyrillic_1.pl
original: 't\'e|t\'i|t\'u|t\'a|.'
suggested: (?^msx: t\'e | t\'i | t\'u | t\'a )
raw: [t'i don't understand t'any cyrillic.]
translation: [&#1090;&#1080; don't understand &#1090;&#1103;ny cyrillic.]