For one definition of "split" and "words", I'd use:

my @words= $string =~ /(\w+(?:'\w+)*)/g;
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Which would give you words like qw( split and words I'd use ) not like qw( "split" and "words", ) nor like qw( words I d use ).

Update: Or even, allow hyphenated-word capturing:

my @words= $string =~ /(\w+(?:[-']\w+)*)/g;
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