At your own risk, splitting on tab:

use strict;
use warnings;

open my $words, "<", "words.txt" or die "Cannot open words.txt: $!\n";

my $lasttype;
my @text;
while( <$words> ) {
        chomp;
        my @row = split /\t/;
        my $text = $row[0];
        my $type = ( $row[-1] =~ /\w-(\w+)/ ) ? $1 : "";
        $lasttype = $type unless @text; # special treatment for first 
+row
        if( $type eq $lasttype ) {
                push @text, $text;
        } else {
                print '<key="type">'."$lasttype</key><text>@text</text
+>\n" if $lasttype;
                $lasttype = $type;
                @text = ( $text );
        }
}

# print what's left over when all input read
print '<key="type">'."$lasttype</key><text>@text</text>\n" if $lasttyp
+e;

close $words;
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