Pushing into a 2 dimensional array in php

Question

If i have an array with 2 dynamic values like this :

 $people = array(
    "george" => "smith"
);

How can i push into that in php?

I have tried

array_push($people, "john" => "smith");

EDIT :

I have tried what has been commented but adding a new key doesnt create a new entry in the array, there is only 1 value although there should be 3..

 $people = array();

foreach ($items as $item){

    $name = $item->getElementsByTagName('name')->item(0);
    $num = $item->getElementsByTagName('number')->item(0);
    $mess = $item->getElementsByTagName('message')->item(0);

    if($name != NULL && $num != NULL && $mess != NULL){
        $people[$num->textContent] = $name->textContent;

    }

}
 var_dump($people);

Answer 1

If new element has a defined key:

$people['newkey'] = 'newvalue';

Without any defined key:

$people[] = 'newvalue';