First off you don't need to put parens around your variables. And what is going wrong is you're trying to look up values from @phrase, when you don't need to. Here is how I would write this, following your style:

use strict; 
use warnings; 
my @phrase = ( 'apple', 'apple', 'banana', 'banana', pear', 'pear',
'kiwi', 'kiwi' ); 
my %wordfreq; 

# Here $i contains the actual value from @phrase 
foreach my $i ( @phrase ) { 
     $wordfreq{$i}++; 
     print "$i appears ", $wordfreq{$i}, "\n"; 
}
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