<?php

$re = '~\w+[.?!]+\s+(?=\p{Ll})~u'; 
$arr = array("Howdy world? lorem", "Howdy world... lorem", "Howdy world?   lorem", "What is reality. howdy ",
	"Howdy you. Lorem ", "Howdy you. 進撃の "); 
print_r(preg_grep($re, $arr));