my @files = ( "File1", "File2", ... );

my @regexes = ( 'verb [\w<>]+\s+/', 'noun \w+\s+/', ... );

for my $file ( @files )
{
	my $regex = qr/shift @regexes/;

	...

    $sizes{ $version }{ $file } ++ if /$regex/;
}

##</code><code>##

Use of uninitialized value $regex in regexp compilation at ./compare.lexicons.pl line ...