Essentially the same as 1nickt's approach, except the regex for a word is defined in one place so you can play with it until you get it right, and matches are extracted to an array:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $str = 'mary had a little lamb';
 ;;
 my $word = qr{ [[:alpha:]]+ }xms;
 ;;
 my @words = ($str =~ m{ $word }xmsg)[0 .. 2];
 dd \@words;
"
["mary", "had", "a"]
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