while (<REGEX>) {
  chomp;
  my ($key,$value) = split (\t,$_);
  $value = "\"$value\"";
  if ($key=~s/^\w+$/) {
    $simple{$key}=$value;
  } else {
    $regex{$key}=$value;
  }
}

while (<INPUT>) {
  s/$key/$regex{$key}/gee foreach my $key (keys %regex);
  foreach (split (/\s+/,$_)) {
    if (exists($simple{$_})) {
      push (@line,$simple{$_});
    } else {
      push (@line,$_);
    }
  }
  print OUT "@line\n";
}