<?php
$s = "«Добрый день!» - сказал он, потянувшись…";
$res = preg_split('/\b(\p{Cyrillic}+\W*)/u', $s, NULL, PREG_SPLIT_DELIM_CAPTURE
| PREG_SPLIT_NO_EMPTY
);
PD9waHAKCiRzID0gIsKr0JTQvtCx0YDRi9C5INC00LXQvdGMIcK7IC0g0YHQutCw0LfQsNC7INC+0L0sINC/0L7RgtGP0L3Rg9Cy0YjQuNGB0YzigKYiOwokcmVzID0gcHJlZ19zcGxpdCgnL1xiKFxwe0N5cmlsbGljfStcVyopL3UnLCAkcywgTlVMTCwgUFJFR19TUExJVF9ERUxJTV9DQVBUVVJFIHwgUFJFR19TUExJVF9OT19FTVBUWSk7CnByaW50X3IoJHJlcyk7