open( INPUT, "<:utf8", "input" ) or die "input: $!";
open( OUTPUT, ">:utf8", "respelled" ) or die "respelled: $!";

while (<INPUT>) {
    my $outstr = '';
    for my $tkn ( split /(\s+)/ ) {
        if ( exists( $respell{$tkn} )) {
            $tkn = $respell{$tkn};
        }
        $outstr .= $tkn;
    }
    print OUTPUT $outstr;
}