$re = '/".*?"(*SKIP)(?!)|(?<!\w)\'.*?\'(?!\w)(*SKIP)(?!)|[\w\']+/';
$str = 'This is some text, it isn\'t limited by single quotes in words like "isn\'t" for instance.
Text quoted in "double quotes" will not be counted.
Text quoted in \'single quotes\' won\'t be either.
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php