A modified sentenceNormalizer by gregomm
 
Features:
1- Removes duplicated question marks, exclamations and periods
2- Capitalize first letter of a sentence.
3- Split sentences not only with "." but also with "?" and "!"
4- Puts a white space at the end of each sentence
5- Retains newlines

--removed from orginal function--
undestand the meaning of "¡" and "¿" in languages like spanish.
undestand the htmlentitity version of this simbols.
--removed from orginal function--

<?php
function sentenceNormalizer($sentence_split) {
    $sentence_split = preg_replace(array('/[!]+/','/[?]+/','/[.]+/'),
                                   array('!','?','.'),$sentence_split);        
    
    $textbad = preg_split("/(\!|\.|\?|\n)/", $sentence_split,-1,PREG_SPLIT_DELIM_CAPTURE);
    $newtext = array();
    $count = sizeof($textbad);
    
    foreach($textbad as $key => $string) {
        if (!empty($string)) {
            $text = trim($string, ' ');
            $size = strlen($text);
            
            if ($size > 1){     
                $newtext[] = ucfirst(strtolower($text));
            }
                elseif ($size == 1) {
                    $newtext[] = ($text == "\n") ? $text : $text . ' ';
                }      
        }
    }
    
    return implode($newtext);
}
?>