#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my @strings = (
  q|one two 'three' one|,
  q|yes i am 'sme'|,
  q|x21 y z|,
);

for my $str (@strings){
  my %hash;
  for ( map { length >= 3 ? $_ : () } $str =~ /(\w+)/g ) {
     $hash{$_}++;
  }
  print Dumper(\%hash);
}