use strict;
use warnings;
my $text = "I will not stir from this place, do what they can.";

my %replacements = (
                     "will not"         => "won't",
                     "stir"             => "move",
                     "this place"       => "here",
                     "do what they can" => "let them try");


my $pattern = join "|", map quotemeta, keys %replacements;

print "The pattern is: $pattern\n";
my $replaced = $text =~ s/($pattern)/$replacements{$1}/gr;

print $replaced;