<?php
function getRandomWord($len = 10) {
    $word = array_merge(range('a', 'z'), range('A', 'Z'));
    shuffle($word);
    return substr(implode($word), 0, $len);
}

for ($i = 0; $i < 10; $i++) {
    echo getRandomWord()."\n";
}

ydxnzAeOhv
fERdqTcBWX
CBlEmNVhQW
qXdmJvxLDF
suRKQVYcGL
ZFIJmrfkzG
tZfjCxIPYh
MECRUiSuWd
shtKFbmgRd
EmesMiVbuW