PHP string concatenation

One step (IMHO) better

$result .= $personCount . ' people';

while ($personCount < 10) {
    $result .= ($personCount++)." people ";
}

echo $result;

Just use . for concatenating. And you missed out the $personCount increment!

while ($personCount < 10) {
    $result .= $personCount . ' people';
    $personCount++;
}

echo $result;

This should be faster.

while ($personCount < 10) {
    $result .= "{$personCount} people ";
    $personCount++;
}

echo $result;