#!/usr/bin/perl

$Lang{$L}{"Repl"} = { "m" => "Monat" };  # mimic Date::Manip
$_ = "Mär";

print "before: $_\n";

foreach $from (keys %{ $Lang{$L}{"Repl"} }) {
  $to=$Lang{$L}{"Repl"}{$from};

  utf8::upgrade($from);  # Use Unicode semantics
  s/(^|[^[:alpha:]])$from($|[^[:alpha:]])/$1$to$2/i;
}    
print "after:  $_\n";

##</code><code>##

before: Mär
after:  Monatär

##</code><code>##

  s/(^|[^\p{IsAlpha}])$from($|[^\p{IsAlpha}])/$1$to$2/i;

##</code><code>##

before: Mär
after:  Mär